Module 12- Track Inspections & Maintenance*
Welcome to the Track Inspection portion of the Practical Guide to
Railway Engineering Seminar.
My name is ____________________. I work for ___________________ and
I have been in the railway industry for ________ years.
As you will see in the following slides, Track Inspection is one of
the most important aspects of track maintenance.
Feel Free to ask questions throughout this segment as the
presentation will be short and not extremely detailed.
COPYRIGHT © AREMA 2010
12: * of 55
Application of the Track Safety Standards
Specialized Inspection Vehicles
October 2007
The title of this Module is Track Inspection and Maintenance.
Track Inspection:
The purpose of track inspection in its many forms is to ensure that
the track is first and foremost safe to operate and secondly, that
it remains at the maintenance level desired.
We will look at how inspections are performed and why we do certain
types of inspections.
We will explore the FRA Track Safety Standards to illustrate
examples of track defects found through the various modes of
inspection and how they are handled in the context of our
operations.
And finally, we will touch upon the use of today’s technology to
measure the quantitative attributes of the track structure.
Track Maintenance:
In this module, we wish to gain some familiarity with basic
elements of railway track maintenance. It is important that you
have an understanding of how we maintain railway functions so that
your design and construction projects are seamless with our
operations. Although you may not be supervising rail relay or
timbering gangs, you may have to integrate these functions into
your project in order to complete it.
At the conclusion, you will hopefully have a basic understanding of
track inspection and maintenance practices and how it relates to
overall operations. We want you to remember that what you build, we
have to maintain.
COPYRIGHT © AREMA 2010
12: * of 55
First and Last “Line of Defense” against track related
derailments
Initial phase of planning for maintenance activities and future
track upgrade programs
Public and employee safety
*
Besides being a regulatory requirement, track inspections are a
vital part of ongoing track maintenance, and are often the first
and last line of defense against track related derailments.
Inspections are also an important part of the track maintenance
planning process. As will be evident in the following slides,
specific methods of inspection are utilized to plan future
maintenance activities.
Most importantly, quality track inspections are essential in order
to protect our railroad employees and the public at large from
track related train accidents.
COPYRIGHT © AREMA 2010
12: * of 55
Hi-rail Inspections
Walking Inspections
Train Inspections
Each of these will be discussed separately beginning with the
Hyrail.
COPYRIGHT © AREMA 2010
12: * of 55
Inspection By Hi-rail
Hi-Rail
The hi-rail is a versatile vehicle that allows the inspector to
traverse the track in one direction and return by road
Provides flexibility/versatility
Most often one, and sometimes two Inspectors observing the
track
Scheduled per regulatory requirement and/or company policy
Visual detection of defects
“Feel” and sound of the track that may indicate the presence of a
substandard condition
October 2007
*
The Hi-rail inspection - Is conducted most often as it allows the
inspector to cover more track than if walking, but also allows
him/her to view the track close enough to detect track defects.
Most of the “main track” required inspections are performed by
hi-rail.
Since regulations were introduced requiring minimum inspection
frequencies (in some cases 2 or more times per week), the hi-rail
vehicle has become an indispensable asset for the track inspector.
The on-rail-or-road flexibility of the hi-rail has drastically
reduced the “unproductive time” of waiting in remote sidings for
trains or work crews to clear. Often the inspector can plan his/her
inspection around trains and maintenance crews as they are able to
remove the hi-rail at road crossings and travel to another section
of the railway to continue on with their inspection.
In addition to the visual aspect of an inspection, a seasoned track
inspector will use other senses during the course of an inspection
including the “feel” of the track and distinct “sounds” that may
indicate an abnormal condition.
Some primary inspection items include; Broken rails or rails pulled
apart at a joint, unusual marks on the rail, broken or missing
bolts, general surface and alignment deviations, standing water in
ditches, signs of unstable grade, ballast condition, clusters of
defective ties, high spikes or missing fasteners, damage to railway
signs and signals, general condition of turnouts, condition of road
crossing surfaces, and several other items far too numerous to
cover in this session.
Track inspections are most often performed by one inspector, but at
times they may be accompanied by an assistant or track
foreman.
COPYRIGHT © AREMA 2010
12: * of 55
Quantify defects with physical measurements
Planned at various times of year, or;
Company policy may dictate an annual walking inspection.
Regulatory requirement for inspecting turnouts, track crossings and
lift rail assemblies or other transition devices on moveable
bridges to be performed “on foot”
Walking Inspections
October 2007
*
Secondly, The Walking Inspection - May be performed for various
reasons, numerous times a year, on any given track. Some railroads
may even require their inspectors to cover the entire main track
territory on foot every year. For the most part however, walking
inspections are performed when it is necessary to get a closer look
at a particular segment or aspect of the track structure.
Walking inspections are often an integral part of planning major
maintenance programs such as rail and tie replacements.
In addition, FRA Track Safety Standards and Transport Canada –
Track Safety Rules dictate that; Inspection of switches, track
crossings, and lift rail assemblies or other transition devices on
moveable bridges”, shall be inspected “on foot” (walking) at least
monthly.
The on foot inspection is stipulated for good reason.
Realistically, the measurements required for an adequate inspection
of these types of track works can only be done from the ground with
a tape measure or other measuring device in hand. In addition, the
several moving parts of a turnout or lift assembly need a close
look for signs of wear and proper fit. Simply put, this can only be
accomplished by getting down – and often dirty - with your
track.
It cannot be stated enough that an “on foot” inspection can reveal
conditions that may never be detected from a hi-rail vehicle.
COPYRIGHT © AREMA 2010
12: * of 55
Provides a “feel” of the track under loaded conditions
Frequency depends on amount and type of train traffic, anywhere
from twice annually to monthly
No regulatory requirement – Company Policy
Train Inspection
October 2007
*
And lastly, The Train Inspection – Performed to get an overall
indication of the track geometry under load and observe the ride
quality, primarily for passenger trains, but also freights.
The availability and flexibility of hi-rail vehicles, in addition
to advancements in track geometry vehicles, have diminished the
need for “train ride” inspections.
COPYRIGHT © AREMA 2010
12: * of 55
Emergency (Weather related, Incidents/Accidents)
*
There are also three types or “reasons” for a Track Inspection.
Once again, each will be discussed individually.
Scheduled inspections – Covering compliance with regulatory and
company standards
Special Inspections – Covering specific locations or conditions as
well as Emergency situations
Specialized Vehicle Inspections – Specifically Rail Flaw and Track
Geometry test vehicles
COPYRIGHT © AREMA 2010
12: * of 55
Regulated, Mandatory inspection of Main track and sidings (Hi-rail
or Walking)
Monthly Inspection of “Other than Main” track, Turnouts &
Special Track Work (Walking)
FRA/Transport Canada outlines minimum inspection frequencies
Report of tracks inspected, conditions found and actions taken are
completed during the inspection.
Scheduled Inspections
October 2007
*
Scheduled Inspections are for the most part conducted as per
regulatory requirements, which vary in frequency depending on the
class of track and the amount of tonnage hauled over a segment of
track.
These scheduled, or “routine” inspections are performed primarily
by hi-rail vehicle, although as previously discussed, turnout and
other track work inspections are conducted on foot.
Track Work, as defined in regulations includes; Track Crossings at
Grade (diamonds), Lift Rail Assemblies (Drawbridges), or other
transition devices on moveable bridges.
A railway company may initiate more frequent scheduled inspections
than called for by regulation. However, minimum frequencies as
outlined by regulation must be followed.
In addition to the inspection itself, there are reporting
requirements outlined by the regulation, which we will cover in
more detail in a few minutes.
COPYRIGHT © AREMA 2010
12: * of 55
Track Safety Standards
GENERAL
ROADBED
*
The Federal Railroad Administration sets minimum standards for the
maintenance and inspection of track in 46 CFR 213 Track Safety
Standards. In most cases but not all, the criteria are speed
oriented, meaning the tolerances become more restrictive as the
speed goes up. These standards are far below what are deemed good
maintenance or design practices. In fact, if one uses the FRA Track
Safety Standards as a maintenance standard, it is almost certain
the railroad will not be operating at that speed for very long. The
Track Safety Standards are applicable to any railroad deemed part
of the general transportation system (interchanging freight cars to
and from their trackage). Most rapid transit systems, industrial
plant trackage and railway museums are not part of the general
transportation system; however, many adopt the Track Safety
Standards as a minimum.
The Track Safety Standards are broken up into 6 primary segments.
Subparts A – F are concerned with freight train speeds up to 80 MPH
and passenger speeds up to 90 MPH. Additional more restrictive
standards are published for passenger trains operating at speeds in
excess of 90 MPH as is done by Amtrak in the Northeast Corridor or
on the west coast.
Canadians under the auspices of Transport Canada utilize a similar
set of minimum standards with but a few minor exceptions.
AREMA FRA 213 CLASS
Quantitative
*
The FRA Track Safety Standards classifies defects in one of two
ways.
As already mentioned, most defects are tied to the speed of
operation. Acceptable and measurable parameters are compared
against established measurements or allowable deviations ranges of
speed. As the speed ranges increase, the tolerances or acceptable
deviations become more restrictive. Should the track structure not
meet up with the requirements, one must either repair the defect,
restrict the speed down to a class of track that finds the
measurement made acceptable, or remove the track from train
operations until the defect is repaired to at least acceptable
parameters for the bottom range of speed. (Gage, alignment.
Surface. Etc. are examples
Other defects are not tied to a specific speed range, but when
found require action. For example rail defect remedial action is
based on the size of the defect. There are non-class specific
defects that are not measurable, but are dependent on whether or
not the specific function is capable of performing its task.
Drainage and vegetation are examples. Either the drainage structure
is capable of performing it’s task or it isn’t. These defects may
be somewhat subjective and often the presence of other related
defects are used to determine whether a qualitative non-class
specific defect exists. Per the FRA/Transport Canada, a defect may
exist if even though in isolation individual parameters meet the
minimum requirements, but combined together a condition exists that
may peril train operations (213.1).
Track inspectors locate defects primarily through visual
observations. It may be readily apparent such as the bolts sheared
and the rails pulled apart at a joint or a broken rail. Other
defects may not be as readily apparent and are determined through
sophisticated machines, e.g. ultra-sonic inspection of the
rail.
In any case, once a defect is determined to exist one of the three
R’s (Repair, Restrict, Remove) must be applied before the first
train.
COPYRIGHT © AREMA 2010
12: * of 55
213.7 Designation of Qualified Persons to Supervise Renewal &
Inspect Track
213.13 Measuring Track Not Under Load
213.15 Penalties
213.17 Waivers
*
This section of the standards is concerned with the regulatory
aspects of the regulation. The speeds associated with each class of
track are defined for both freight and passenger operations. These
are the maximum speeds that may be operated for a given class of
track. Should the speed operated be between two class of track
maximum permissible speeds, the class of track is automatically
designated as the next higher class of track. Railroads, upon
discovering a defect not in compliance with the class of track for
the speed which they desire to operate, must immediately repair the
defect or restrict the speed to a class of track to which they will
be in compliance or remove the track from service until the repair
is completed.
The FRA denotes a special class of track known as Excepted Track.
Many of the smaller short lines are formerly unprofitable branch
lines spun off from Class 1’s. Their inability to generate adequate
revenues in the past relegated them to receive little if any
capital improvement dollars. In many cases, they will not meet the
minimum requirements for Class 1 track. The owners will not have
access to the funds required to bring the track in compliance with
Class 1 track. Yet these short lines are indispensable to the
vitality of the nation’s economy. The FRA permits these railroads
to designate trackage not meeting Class 1 requirements as Excepted
Track. Such railways may operate at Class 1 speeds (10 MPH) without
bringing the track into compliance. There are restrictions
regarding the movement of hazardous material cars and passenger
trains, minimum spacing required between excepted track and track
operated at higher than Class 1 speeds as well as a maximum
permissible value for gage.
This subpart of the Standards also defines the criteria associated
with who can supervise restoration or renewal of track and who can
inspect track.
COPYRIGHT © AREMA 2010
12: * of 55
*
Subpart B, Roadbed describes the minimum requirements for roadbed
and area immediately adjacent to the roadbed. This section of the
Standards is not class specific – meaning there is not a prescribed
remedial action for a given defect. Qualified railway personnel
determine an appropriate remedial action for drainage or vegetation
related defects based on their experience and the conditions
peculiar to a given operating situation.
The FRA stipulates that each drainage or water carrying facility
under or immediately adjacent to the roadbed must be maintained and
kept free of obstruction to accommodate expected water flow for the
concerned area.
The FRA further requires that vegetation be controlled so that it
does not become a fire hazard to track carrying structures;
obstruct visibility of signs and signals along the right-of-way and
at highway rail crossings; interfere with railroad employees
performing their trackside duties or prevent them from inspecting
moving equipment from their normal duty stations; or prevent signal
and communication lines from functioning.
Ask: Based on the photos depicted on the slide, are there defects
present?
Answer: Certainly, the presence of sanding water reflects a blocked
or collapsed culvert, The vegetation under the bridge could become
a fire hazard during the dry months.
COPYRIGHT © AREMA 2010
12: * of 55
213.63 Surface
October 2007
*
Subpart C, Track Geometry deals with how the car wheel-sets
interact with the track structure. The minimum requirements for
gage, alinement, surface of the track, elevation of outer rails in
curved track and speed limitations in curves are defined.
We will provide special focus on gage, alinement and the special
parameters associated with surface. We have already dealt in a
previous module with the maximum permissible speed that can be
operated around curves based on elevation and degree of
curvature.
COPYRIGHT © AREMA 2010
12: * of 55
4
4
*
Gage refers to the distance measured between the heads of the two
rails at right angles to the rails in a plane 5/8” below the top of
the head. Track is built in North America, with but few exceptions
on transit and museum lines to a standard gage of 56-1/2” (4’
8-1/2”). The inside face of wheel to inside face of wheel dimension
is 53-1/4” (4’ 5-1/4”). This permits some movement of the wheel to
enable the wheel flanges to float between the two rail heads and
yet for the wheel tread to still ride on the rail. However when the
gage becomes two wide, the wheels may literally drop in. As a train
moves down the railroad, the wheels tend to hunt back and forth
between the gage corners of the rail. Each time the wheel flange
impacts the rail gage corner, a lateral load is applied to the
rail. As the speeds increase, this lateral load goes up by a factor
of the square. As the wheel runs around a curve, centrifugal force
causes the wheel flange to ride up against the gage corner of the
outer or high rail – again imparting significant lateral loading.
This lateral loading eventually causes spike hole enlargement and
tie deterioration. The end result is wide gage.
The FRA Track Safety Standards also specifies minimum gage. Gage
too tight can cause the wheel to climb the rail and thereby
derail.
Typically, the wheels will fall in when the gage under load exceeds
2”. The FRA sets a maximum permissible wide gage for Excepted Track
at 1-3/4”. There is no relief from this provision for even Excepted
Track.
Gage defects are a constant source of headaches for railway
engineers.
Ask: Can you spot the defect in the photo. The sharp kink in the
closure rail is wide gage. This is a frequent spot for gage
problems in turnouts.
COPYRIGHT © AREMA 2010
12: * of 55
*
Alinement refers to the horizontal positioning of the track
structure. In tangent track, the track is straight if we lay a
string of any length along the gage face of the rail and the string
touches the rail at every point. For referencing purposes, a 62’
string is stretched along the gage face of the rail with the
midpoint of the string at the location that by eye appears to be
the most out of line. The mid-ordinate distance between the string
and the gage corner of the rail – 5/8” down represents the maximum
deviation from the desired 0”. The Track Safety Standards specifies
for a given Class of track the maximum deviation permissible for
tangent track. If the mid-ordinate measurement exceeds that value,
railways must either correct the alinement defect or reduce to a
class of track for which the mid-ordinate measurement read is in
compliance.
In curves, there should be a mid-ordinate value read when using the
62’ string. Remember, the mid-ordinate value read at the midpoint
of a string in inches for a 62’ chord reflects the actual degree of
curvature at that spot. However the difference in the actual
mid-ordinate value read and the average value for the curve is the
deviation. The deviation exceeding the value found in the Alinement
Table for the 62’ chord for a given class of track will require
that the defect be corrected or the speed of the track be dropped
to a speed which it will be in compliance. For Classes 3 through 5
track, the FRA also requires that one use a 31’ chord to check for
deviation in addition to the 62’ chord. It is theoretically
possible to hide a short sharp line spot inside of a longer badly
out of line location. This short sharp spot might not be revealed
with the longer chord but will be evident with the shorter
chord.
Tangent Track
Curved Track
Class of Track
The deviation of the mid-offset from a 62 foot line may not be more
than
The deviation of the mid-ordinate from a 31 foot chord may not be
more than
The deviation of the mid-ordinate from a 62 foot chord may not be
more than
Class 1
*
Surface refers to the relationship defined by the longitudinal and
transverse relationship of one rail to the other. In most cases,
permissible surface deviations are much more restrictive than for
alinement and are a leading cause of derailments.
We will discuss several critical surface parameters including
run-off, profile, deviation from uniform crosslevel in tangent and
maximum reverse crosslevel in curves, difference in crosslevel
within 62’ or warp, and harmonics.
COPYRIGHT © AREMA 2010
12: * of 55
*
Runoff conditions are usually a result of some kind of track
maintenance activity. Trains encountering a ramp (up or down) will
experience a vertical pitch or bounce if the runoff is too abrupt
or short. As in the more general profile parameter, damage to car
components, damage to customer’s freight, undesirable brake
applications, or derailments may occur.
Run-off is measured by stretching a 62’ string along the top of the
rail with the midpoint of the string at the point that the rail
begins to ramp down or up. The remainder of the string is stretched
out over the rail ramping up or down with the first 31’ of string
just maintaining contact with the head of the rail. The distance
from the end of the string down to the rail then becomes the
run-off in 31’ Maximum permissible values for each class of track
are provided in the surface table
Run-off in this photo is located at the transition point from an
open deck bridge to a ballast decked bridge. Run-off is commonly
found off the ends of bridges where the track modulus for more
rigid bridge structure transitions to the smaller modulus of the
track itself.
COPYRIGHT © AREMA 2010
12: * of 55
*
Trains encountering short sags or humps in the track can cause
vertical separation of couplers, broken springs, bolsters, and
truck frames, as well as damaging customer’s freight. Sags can
result from mud spots, or develop at the ends of fixed structures,
i.e., bridges, highway grade crossing and track crossing
frogs.
The profile measurement is made along one rail by stretching a 62
foot string on the top of the rail and placing the midpoint of a
62-foot chord at the point of concern, irrespective of vertical
curves. Then the distance between the string at the mid point and
the top of the rail is measured. The measured deviation is compared
to the maximum permitted for the appropriate class of track.
Profile may also be a track hump cause by a frost heave or other
occurrence. The most common profile problems found are sags.
The profile in the photo above is probably the result of a subgrade
failure.
COPYRIGHT © AREMA 2010
12: * of 55
*
The next surface parameter is deviation in crosslevel in tangent
track and maximum allowable reverse elevation in curves. These are
single spot measurements. In tangent track, the crosslevel reading
should be 0”. Anything else is a deviation and is compared to the
table for the appropriate remedial action. The same table is used
to determine the maximum allowable reverse elevation reading.
Remember, in both cases to add any movement under load.
Ask the class how to measure the crosslevel at this location.
Ask the class what defects might exist at this location and what is
the root cause of the problems at this location.
Also note to the class that conditions such as this at an insulated
joint can cause signal failures and premature failure of the
insulated joint. The joints are expensive and stopping trains due
to signal failures is very expensive.
COPYRIGHT © AREMA 2010
12: * of 55
Difference In Crosslevel
*
Difference in crosslevel or warp compares how the crosslevel
changes from one spot to another anywhere within 62’ on tangents,
curves, and spirals. It is a reflection of what the car experiences
as the lead wheels react to a low joint on one rail simultaneously
to the rear truck wheels reacting to a low joint on the opposite
rail. The twist experienced by the car can cause wheel lift with a
resulting derailment. Warp is calculated by finding the two largest
crosslevel readings within 62’ on opposite rails and adding them up
to get a difference in crosslevel reading or finding the largest
and smallest crosslevel readings on the same rail within 62’ and
subtracting the readings to obtain the difference in crosslevel.
These values are then compared to the maximum permissible values
found in the Surface Table.
Although warp in the field is probably the most difficult surface
deviation to detect, it is generally the most limiting and should
be always checked when low joints are present.
In the slide photo, we see a very low joint in the far rail and
another low joint in the near rail. Crosslevel readings would be
taken at each joint, potential movement under load added and the
two crosslevel readings added to determine the difference in
crosslevel or warp.
COPYRIGHT © AREMA 2010
12: * of 55
*
For any body in motion, there is a critical speed at which if
imparted harmonic movement of a given frequency, resonance will
occur with the resulting amplitude becoming progressively larger
until failure occurs. For many freight cars, they can go into
resonance at speeds between 17 – 22 MPH if they encounter a series
of low joints on opposite rails with a difference in crosslevel of
1-1/4”. This surface condition is deemed possible if 7 consecutive
low joints (6 difference in crosslevel readings) are all found to
have a difference in crosslevel greater than 1-1/4”. This condition
is not applicable for joint staggers less than 10' or for 80'
rails. Joints outside normal stagger, insulated joints, plugs,
etc., are not included as harmonic joints. It does not apply to
CWR. The remedial action required is to either raise one or more of
the low joints to break the pattern or reduce the speed to 10 MPH
(below the critical speed required for resonance. Extreme harmonic
conditions can cause high center of gravity cars (loaded covered
hoppers, etc.) to rock off and derail.
COPYRIGHT © AREMA 2010
12: * of 55
October 2007
*
Subpart D, Track Structure prescribes the minimum requirements for
ballast, crossties, track assembly fittings and the physical
conditions of the rails. The remedial actions are a mixture of type
and course of action. For some like ballast, there is no specified
remedial action. For rail defects, there are specified remedial
actions, but they are independent of speed. Others like mismatch
between gage and tread faces are class specific.
We will concern ourselves with two sections of Subpart D: Crossties
and Defective Rail as both are essential components of the track
structure.
Top Photo – 213.137(c) worn tread of frog requiring 10 mph slow
order.
Bottom photo – 213.135(b) switch point not properly fitting against
the stock rail.
COPYRIGHT © AREMA 2010
12: * of 55
PER 39’ RAIL LENGTH
Definition of Defective Tie
Joint Tie Conditions Fulfilled
Non-Defective Ties Effectively Distributed
Tangent track and
*
The crossties in the track serve to provide three functions. First
to maintain gage, second to maintain surface and third to maintain
alinement. In newly constructed track, all ties are serviceable.
Immediately after the track is placed in service, this condition no
longer holds true. Not every tie has to be capable of performing
each of the three functions. But the aggregate system must do so in
order to carry the applied loads.
What is a defective tie? In general any tie that is broken through,
split or otherwise impaired to the extent that the crossties will
allow ballast to work through, or will not hold spikes or rail
fasteners, or so deteriorated that the tie plate or base of the
rail can move laterally more than 1/ 2 inch relative to the
crossties or cut by the tie plate through more than 40% of the
crossties thickness is considered to not be an effective
crosstie.
The FRA defines the minimum number of effective ties per 39’ that
must be present. Note: The average rail length contains 22 – 24
ties depending on tie spacing. Thus only ½ the ties in a rail
length for Class 4 or 5 track need be serviceable. The requirements
are somewhat more restrictive in turnouts and curves of 2 degrees
or greater.
The FRA further says the serviceable ties must be effectively
distributed. Although that does not mean evenly spaced; there does
have to be some common sense distribution throughout the entire
rail length.
Joints are a particularly weak area in the track structure. Special
attention dependent on the class of track is specified for
distances between centerline of joint and the centerline of the
closest non-defective tie
COPYRIGHT © AREMA 2010
12: * of 55
Defects Longitudinal
Split Web & Piped Rail
October 2007
*
The process of locating and removing a defective rail prior to a
train finding it is obviously a high priority for any railway.
Ultrasonic or combination ultrasonic and electro-induction testing
of mainline rail is required by the FRA for railways operating
above Class 2 speeds. The frequency of testing is determined by
whether or not passenger trains operate over it, the designated
class of track and the annual tonnage operated over the track
segment. Class 1, large regional and commuter railways test at much
higher frequencies than the FRA requirements.
Not all defective rails are located by test vehicles. Many defects
have a signature trail that a sharp eye performing routine track
inspection can pick up. Some break but are detected by the
fail-safe system provided by the track circuit in trackage
controlled by a signal system. Regardless all rail defects are
dangerous and must be removed from the track. The FRA remedial
actions are not class specific. The particular remedial action is
governed by the size or length of the defect and its nature. Any
complete breakout in the rail requires that the rail be immediately
changed prior to allowing a train over it, or that the track be
removed from service or that every movement over the broken rail be
supervised by a qualified employee at walking speed. Track
designated as Excepted Track is exempt from the remedial actions
required for defective rails, but there is a presumption that
movement over the rail will not occur unless it is safe to do so.
Remember speeds associated with Excepted Track are limited to 10
MPH and passenger trains are not permitted.
Rail defects can be broken down into two major classifications:
defects that represent a percentage of the cross-sectional area of
the head and defects that represent a given longitudinal
length.
COPYRIGHT © AREMA 2010
12: * of 55
Transverse & Compound Fissures
*
There are many different type of rail defects. The transverse
fissure and compound fissure are examples of two of the most
dangerous defects. Transverse fissures begin because of a trapped
inclusion or hydrogen bubble located in the head. They are a very
dangerous defect in that there are no visible indications until the
crack reaches the exterior of the head. As older rail rolled prior
to 1943 (advent of controlled cooling) are phased out, their
frequency of appearance is declining. The defect can be recognized
by its center nucleus surrounded by rings much like that of a tree.
When it breaks, the rail frequently shatters with large chunks
breaking out although the primary break is in a transverse
plane.
A compound fissure is similar to a transverse fissure except it
starts in a horizontal plane and then progresses downward.
The required remedial action for defects affecting less than 70% of
the head is relatively innocuous – a qualified individual limit the
speed to 30 MPH or the timetable speed of the track, whichever is
less, transverse defects of either type should be immediately
removed from the track upon their discovery.
COPYRIGHT © AREMA 2010
12: * of 55
*
Detail fractures look like a transverse defect, but originates from
the outside gage corner of the rail and usually starts from shells.
A dark half-moon shaped spot at the gage corner of the rail is a
good indication that a Detail Fracture is forming. These defects
are quite common and are a reflection of the heavy tonnage that
exists on North American railroads today.
When these defects break it quite often results in a derailment
because a piece of rail will completely break out of the track.
Rail detector cars often have trouble detecting this defect.
Engine burn fractures originate out of an engine burn on a rail
from wheel slippage of a locomotive. The presence of a burn on the
rail is not indicative of a fracture. They originate often from a
burn not properly repaired. Inadequate grinding to get to the
bottom of the burn and to remove the micro-cracks prior to laying
down weld bead is often the cause. .A hairline crack on the side of
the head, in the immediate vicinity of an engine burn on the
surface, and at right angles to the running surface may be visible.
The crack may be visible on either the field or gage side of the
head.
Defective welds are caused by the incomplete penetration of weld
metal between rail ends, lack of fusion between weld metal and the
rail ends, entrainment of slag or sand during the thermit welding
process, shrinkage cracking from running a train too soon after
weld completion or fatigue from tonnage operated over it. The
defect involves a field or plant weld with discontinuities or
pockets exceeding 5% of the rail head area individually or 10% in
the aggregate. It is oriented in the transverse plane, may
originate in the head, web or base and may progress from the defect
into either or both rail ends.
These defects complete the defects associated with affecting a
percentage of the cross-sectional area of the rail.
Other types of defects include: horizontal and vertical split
heads, head & web separations, split webs, piped rails, bolt
hole cracks, broken base, flattened rail and ordinary break.
COPYRIGHT © AREMA 2010
12: * of 55
213.205 Derails
Clearly Visible
Properly Installed for Designated Rail Section
October 2007
*
Derails are provide with their own subpart – Subpart E. The
intended purpose of the derail is to direct the wheel of a moving
car, moving along a path that it shouldn’t be going, off of the
rail at slow speeds away from danger of fouling a high speed track.
As such derails are only used in slow speed non-controlled track as
found in yards and sidings. The FRA Standards only specifies what
attributes the derail must possess. The derail must be clearly
visible to an approaching train, must not have lost motion between
the throw lever and the derail mechanism, must operate in the
manner it was intended and must be installed per the manufacturer’s
instructions. Derails are sized by the rail section that they will
be used on. Derail sized for a smaller rail section than the
section in use may not cover the entire head of the rail and may
not derail an approaching car. A derail too large for the rail
section will not be properly supported by the rail and may break
under load rather than derailing the car.
COPYRIGHT © AREMA 2010
12: * of 55
Tie defect Counts
Rail Wear Measurements
Rail Grinding Requirements
often be anticipated)
Special Inspection (Specific)
*
There are basically two types of Special Inspections. The first we
will discuss is a special inspection that is planned, scheduled and
specific in scope.
Planned special inspections are performed for a number of reasons
at various times of the year. Depending on the geographic region
and the type of Railroad operation, there are many different
conditions that may warrant a special inspection. For instance, an
inspector may plan a special inspection of culverts in the late
winter in preparation for the expected water flow from the spring
thaw or in advance of the heavy rain fall season depending on what
part of the country they are in. An inspector may also plan a
periodic inspection of areas where there are known problems related
to the track grade, or an annual audit of “at grade road crossings”
to determine maintenance requirements.
“Detailed” Turnout and Track Crossing inspections are a type of
special planned inspection. Most railways preferring to conduct
them in the spring or fall, and sometimes both.
Many planned inspections are done in preparation for upcoming
maintenance programs or for future planned upgrades to the track
such as major tie renewal or rail relay programs. These inspections
will involve measurements, in the case of rail replacement or rail
grinding programs. For tie renewals it will involve actual
mile-by-mile counts of defective ties.
An example of a special inspection that cannot be pre-planned, but
can be anticipated for certain times of year are those that are
brought on by extreme heat or cold. The majority of Railroad
companies have high and low temperature thresholds that once
reached, will initiate a special inspection.
Those that cannot be planned and are also unpredictable, are
considered “emergency” special inspections (next slide)
COPYRIGHT © AREMA 2010
12: * of 55
*
Emergency Special Inspections are triggered by unplanned events
such as severe weather and other natural anomalies such as
earthquakes.
FRA 213.239 states: In the event of fire, flood, severe storm, or
any other occurrence which might have damaged the track structure,
a special inspection shall be made of the track involved as soon as
possible after the occurrence and, if possible, before the
operation of any train over that track.
The photographs shown on this slide are examples of grade failures
resulting from heavy or prolonged rainfall.
Also unpredictable, especially in mountainous areas are problems
such as rockslides, avalanche and mudslides caused by snowmelt high
above the track.
Tornados and High winds can often leave large trees and other
debris on the track.
Inspecting damage caused by an earthquake is especially difficult,
as there is no way to positively ascertain the area affected and a
special inspection may be required on one or more track inspectors
entire territory to ensure the track grade and structures have not
been adversely affected.
Emergency Inspections may also need to be conducted following
reports of vandalism, track or signal damage as a result of a
vehicle collision with a train, or other types of human factor
related incidents.
COPYRIGHT © AREMA 2010
12: * of 55
List all deviations and the corrective action
Kept on file for 1 year
Type of inspection indicated on report
Signed & dated
Inspection Records
October 2007
*
As the oft heard saying goes – The job is not finished until the
paperwork is done!
All required track inspections, including turnout and special
inspections, are recorded on a Track Inspection Report, and kept on
file for one year.
The reports are to be completed on the same day as the inspection
and require the following information:
The date of the inspection
The track or tracks inspected
The location and nature of any FRA deviations found and the
corrective action taken
And finally the report must be signed by the track inspector.
Some Class I railroads have adopted the use of “Electronic” track
Inspection Reports which are produced “on the fly” by track
inspectors using lap-top computers or Palm Pilots.
COPYRIGHT © AREMA 2010
12: * of 55
Scheduled
Internal search for rail defects using NDT “Ultra-sonic testing
equipment
Specialized Equipment & Training required
*
Although very effective, visual track inspections are limited when
it comes to detecting defects in the rail itself, or track surface
defects that only manifest themselves under loaded conditions.
Technology has come a long way to fill the gaps where physical
limitations have left off and have become a vital tool, enhancing
the complete inspection process.
Rail Flaw Detection Vehicles with ultrasonic equipment and trained
operators are capable of detecting internal flaws in the rail that
the track inspector alone may not find until completely broken out
or a break is imminent.
Prudent Railway companies will plan and schedule rail flaw
detection on a regular basis, the testing frequency based on the
amount of tonnage handled, rail size and condition, occurrence of
field service failures (broken rails) and other criteria.
Regulations specify rail inspection frequencies for Class 4 and 5
track (and in Canada - Class 6 track), and Class 3 track on which
passenger trains operate, however several railways are adopting a
more aggressive strategy against broken rail derailments by testing
more often.
COPYRIGHT © AREMA 2010
12: * of 55
COPYRIGHT © AREMA 2010
12: * of 55
*
Railway Engineering budgets are broken down into two segments –
normal day to day maintenance covered under the Operating budget
and special capital improvement projects covered under AFE’s
(Authority For Expenditure) which is programmed beyond budgeted
operating expenses.
Normal maintenance work is typically directed at the division level
by the division engineer rather than by corporate staff. A large
Class 1 railway may have between 9 and 15 divisions encompassing
half of the United States or Canada. The divisions are further
broken down into territories or subdivisions with the work planned
and directly supervised by local officer level supervision. Each
local supervisor will supervise multiple gangs or teams who
actually perform the work under the immediate direction of a
foreman. Virtually all of the Class 1, larger regional and
commuter/transit railways work under a labor agreement. Many of the
smaller short lines are not unionized. The agreement between the
carrier and the labor organization spells out the specific work
that a craft can perform under normal operations and the conditions
upon which that work will be performed. The agreements are designed
to accommodate the normal maintenance functions typically required
to maintain the infrastructure.
Normal maintenance is designed to keep the railway up to its
standards between major capital improvement or rehabilitation
programs. Production rail and tie renewal, undercutting, complete
bridge structure replacement, out-of-face replacement of catenary
wire or conversion of a signal system from pole line wire to
microprocessor based coded track is not considered normal
maintenance. The primary crafts performing normal maintenance can
be broken down into Track, Bridge & Building, Signal &
Communications and on passenger railways, Electrical.
On an electrified railway, the maintenance of the overhead catenary
or third rail system is accomplished by an electrical gang. In
third rail territory, the gang maintains and replaces/installs the
heavy traction bonds between rail ends, maintains impedance bonds,
replaces pitted third rail, and maintains the extensive cabling
required to energize the third rail.
COPYRIGHT © AREMA 2010
12: * of 55
Basic Track Work
*
Basic track maintenance is accomplished by the section gang which
consists of 2 to 6 employees covering any where between 20 to 200
miles depending on annual train tonnage operated over the
territory, number of turnouts and frequency of operation. The
section gang performs the day to day maintenance required to keep
the track operable. This includes spotting in ties on a localized
basis, raising low spots, changing out defective rail, adjusting
the neutral temperature of CWR, performing mowing or brush cutting
operations, providing flag protection for contractors, maintaining
switches and crossing diamonds, cleaning snow from switches,
repairing road crossing surfaces and many other functions required
to keep the track safe for the movement of trains at timetable
speeds. The section gang is often equipped with a specialized
hy-rail vehicle designed to permit ready access to any track
segment of the section. Hydraulic tools along with truck mounted
electric or hydraulic one-ton cranes facilitate the performance of
heavy and tedious tasks that can now be done by 1/3 to ¼ the number
of men previously required. The sections on a territory or
subdivision(s) are supervised by an officer titled as a roadmaster
or track supervisor or manager track maintenance.
The section is also called upon to respond to derailments and other
natural emergencies such as floods, washouts, slope failures, rock
slides, etc. The section will work around the clock to restore
train operations. On any railway, no expense is spared or effort
required too great when train operations have been disrupted.
The section will also be called upon to provide support for other
track capital improvement projects. Sections may join together to
accomplish larger track projects such as road crossing
renewals.
Each subdivision may possess one or more specialized machine
operators. They operate rail based cranes, backhoes, specialized
track equipment and any other specialty equipment pieces.
Track welders are another subgroup member of the Track Department.
They build up rail ends; repair manganese frog castings; grind
switch point, stock rail, frog and crossing diamond overflow as
well as thermit weld together CWR rail strings.
Work equipment mechanics are the last subgroup. They are charged
with keeping the divisions machinery operable.
COPYRIGHT © AREMA 2010
12: * of 55
Basic Signal Work
*
Normal signal maintenance is split between the signal maintainers
and the signal gangs. A signal maintainer is assigned to a
territory, the length of which is a function of the number of
crossing warning devices, interlockings, switches and signal
appliances found on the territory. The maintainer is responsible
for repairing broken crossing gates, changing bulbs in signals,
replacing broken bond wires at rail ends, performing monthly
Federal mandated crossing warning device tests, adjusting track
resistors and other track circuit functions, maintaining track
batteries and power supplies, maintaining and adjusting switch
machine and circuit controllers, splicing broken line wire,
maintaining insulated joints and relocating and bonding track
circuit feed wires.
The signal gang, typically 4 – 6 men, performs the heavier tasks
including setting foundations and gate mechanisms, installing
cantilever signals, renewing pole line or installing Electrocode,
moving setting and wiring of signal cabins or bungalows and
out-of-face direct burial and installation of signal cable
runs.
The maintainers and signal gang(s) are supervised by a signal
supervisor.
COPYRIGHT © AREMA 2010
12: * of 55
*
Dealing with old man winter is a an expected activity for
railroaders performing routine maintenance in the northern climes.
Once the roadbed freezes up, maintenance work shifts from upgrading
the track structure to coping with the demands of winter. In muddy
track conditions, track must be shimmed as the mud heaves forcing
rail up out of the plates. In extreme cold, rail and welds can
become brittle. Changing out defective rails is a daunting task as
the rail one worked so hard to raise the neutral temperature last
year is now in a highly stressed tensile state. Pull-aparts from
broken bars and sheared track bolts must all be repaired with
minimal delay to trains.
Signal forces must deal with road salt interfering with the track
resistance at crossings, thereby affecting crossing warning
devices.
Out on the main track, gas fired or electric furnace switch heaters
keep snow melted and clear of switch points so that electric
switches throw reliably.
Subgrade failures from saturated fills like the photo (top left)
can drop without warning, Track inspectors must be particularly
vigilant for the signs indicating slope failure. Floods can
inundate the track structure (photo top right). Water more than 6”
above the top of the rail will ground out the locomotive traction
motors. Washouts can occur anywhere along the track. Moving water
will not be deterred. If adequate means is not available to handle
the flow, water will make its own path.
Once the water goes down contractors, earth moving equipment and
ballast and rip-rap trains are mobilized to attend to the
damage.
COPYRIGHT © AREMA 2010
12: * of 55
Maintenance of CWR
*
Track buckles are not the result of an act of God. They result
because of some outside influence providing a lateral or
longitudinal load that the track structure does not have sufficient
moment of inertia to resist. In very hot weather when the rail is
in a highly compressed state, the rail may buckle. This is
particularly likely if the track structure has been disturbed in
combination with rail low neutral temperature and consolidation of
the ballast section has not yet occurred. The buckle may happen
immediately as occurred in this production tie gang or it may occur
later underneath a train as in the bottom left photo. In tangent
track, the buckle often takes the shape of an “S”. In a curve, the
track frequently assumes a “C” shape.
Track buckles are preventable. Engineering out the potential for a
sun-kink ahead or under a train in CWR is achieved through the
adherence to specified procedures utilizing a combination of
limiting speed restrictions applied for a given amount of tonnage
and/or number of trains over a given time period until
consolidation is achieved. The specifics to these procedures will
vary according to the type of traffic, train consist, ambient
temperature, physical characteristics of the railway and speeds
operated. Each railway will have developed CWR policies and
procedures pertinent to their operation. Procedures applicable to
commuter/transit operations may not be applicable to unit train
operations. However, it is essential that individual railway
procedures be followed any time track disturbance occurs. Today,
railways can quickly regain about 80% of the original track
stability through the use of a dynamic track stabilizer.
Thus the goal when performing track work of any kind is to minimize
disturbance. But when disturbance does occur, appropriate measures
must be instituted until the track is again stable while still
safely keeping train delays to the minimum possible.
To adjust CWR for a rail temperature higher than that which it was
anchored, its length must be shortened so that compressive forces
are converted to tensile forces. The rail is cut, anchors are
removed and the amount to be shortened plus 1” for each weld is
removed from the rail end. The rail ends are hydraulically pulled
to together by 150 ton jacks (see slide) to close the gap and a
thermit weld(s) are completed. The track is re-anchored and the
rail segment is now at the new neutral temperature.
COPYRIGHT © AREMA 2010
12: * of 55
Drainage & Vegetation Control
*
The control of unwanted vegetation is another essential maintenance
activity. Railroads typically apply a pre-emergent spray via
hi-rail spray rigs in the early spring to the roadbed for most of
the season control of grasses and broadleaves.
A post emergent late summer application of right-of-way beyond the
roadbed is applied to control broadleaves and brush.
Mechanical cutting of vegetation can be broken down into localized
mowing or chain saw removal of brush and tree species or the use of
on-track based production cutting machines. Many of these machines
are not suitable for use in urban areas because of the debris
thrown and the splintered remains of the tree that is left behind.
However, in more remote locations they are an effective means of
clearing the ROW.
The three most important contributors to quality track are
“drainage, drainage and more drainage”. The track ditch serves to
carry away the water shed from the ballast section. Water trapped
in the ballast section will soon lead to pumping track, fouled
ballast and degraded track geometry and ultimately premature track
component failure.
Specialized equipment such as the Jordan ditcher with extendable
wings clear ditches of accumulated debris and vegetation hindering
the free flow of water. These machines have the capability of
creating the trapezoidal shaped ditch that is resistant to plugging
up and will not undermine the toe of the ballast section slope. The
desired end product is the ditch on the bottom left photo. Other
specialty machines such as this rail bound grade-all and cranes
equipped with clam-shell buckets are used to maintain
ditches.
Roadbed exposed to ponding water are candidates for slope failure
and/or muddy track conditions.
COPYRIGHT © AREMA 2010
12: * of 55
*
Dealing with disasters of any kind is a prime component of the
staff performing normal or routine maintenance.
These disasters can be a result of human failure beyond the
railroad’s control such as this collision between Amtrak and a log
truck or it could be the result of carelessness or a lack of
attention to good train handling techniques.
Some disasters are a result of a mechanical failure such as a
shifted load, dragging brake rigging, broken wheel or burned off
journal, perhaps missing side bearings or a host of other related
causes. The failure may be track induced such as a broken rail (the
photo top right) or surface defect, or a result of a track buckle.
The pile-up when it occurs can be awe inspiring. The damages to
rolling stock and lading amounting to millions of dollars. Damages
can even grow higher if hazardous materials are released.
Fire whether on the right-of-way or a bridge, which is often beyond
the railroad’s control must be contained and the damages quickly
alleviated.
Washouts, slope failures or floods also must be dealt with. The
slide lower right shows a locomotive at the bottom of what once was
a high fill. Notice the rail and few ties still attached swinging
high over the unit.
Whatever the cause, the men and women making up the railway
engineering department will spare no effort to return the line to
service and to initiate actions that will prevent further
occurrences of the same type.
COPYRIGHT © AREMA 2010
12: * of 55
*
Next, let’s look at the programmed maintenance activities. These
are typically capitalized.
COPYRIGHT © AREMA 2010
12: * of 55
Purpose: Remove Surface Imperfections in the Rail & Optimize
Rail/Wheel Contact Area
Out-of-Face & Switch Multiple Stone Grinders
Grinds Main Track Based on Railroad Policy
Grinds 6 to 15 MPH
October 2007
*
Rail grinding is another maintenance activity that promotes
increased rail life. Both the rail and the wheel have a radii at
the contact point and when both are new results in the contact
point being over the web of the rail. As rail wears the actual
point of contact moves from the ideal location which causes
increased rail and wheel wear. Rail grinding will re-establish the
proper point of contact resulting in the correct L/V ratio and
improved rail and wheel life.
Rail grinding is achieved through the use of specialized grinding
machines or trains equipped with adjustable grinding wheels that
can remove small amounts of metal at a very controlled rate in a
series of passes. Depending on the amount of material to be removed
and the number of stones utilized, grinding is typically performed
at speeds ranging from 6-15 MPH. A typical switch grinder has 20
stones, while a production grinder commonly has 88 stones. Grinding
is also used to remove surface imperfections in the rail such as
checking and spalling on the low rail and corrugations on the rail
head. Corrugations in transit properties produce the infamous
roaring rail sound. In freight and commuter territory, it can
eventually lead to detail rail fractures.
Rail grinding needs to be closely coordinated with weather
conditions due to the potential for starting right-of-way fires.
The grinders normally have a large water supply with them and wet
the track area as they go however, in extremely dry conditions the
potential for fires is very high.
2009 average daily cost for production rail grinding was
$45,000.
COPYRIGHT © AREMA 2010
12: * of 55
ALUMINOTHERMIC (THERMIT) WELDING (shorter life, local maintenance,
etc.)
Thermit welding (top left) is a welding process, which produces
coalescence of metals by heating them with superheated liquid metal
from a chemical reaction between metal oxide and aluminum without
the application of pressure. Filler metal is obtained from an
exothermic reaction between iron oxide and aluminum. The
temperature resulting from this reaction is approximately 2500° F.
The superheated steel is contained in a crucible located
immediately above the weld joint. The superheated steel runs into a
mold, which is centered around the rail ends to be welded. Since it
is almost twice as hot as the melting temperature of the base
metal, melting occurs at the edges of the joint and alloys with the
molten steel from the crucible. Normal heat losses cause the mass
of molten metal to solidify, coalescence occurs, and the weld is
completed.
FLASH BUTT WELDING (factory welds, high production, longer
lasting)
Flash Butt Welding (top right) aligns the rail, charges rails
electrically and hydraulically forges the ends together. The welder
head automatically shears upset metal to within 1/8" of the rail
profile. A base grinder removes the 1/8" flashing material from the
rail, which leaves a smooth base and greatly reduces the likelihood
of stress risers, which shorten the life of the rail. The sides and
head of the rail are also ground to the profile of the parent rail.
As a final step in the welding process, a mag particle test is
performed. These quality checks, plus separate checks with a
straightedge and taper gauge, contribute to the complete job that
makes a quality weld. Thermite welding
COPYRIGHT © AREMA 2010
12: * of 55
*
In all but the smallest crossings, the crossing track structure is
often pre-paneled out adjacent to the crossing (top left) or at
some other convenient location. The completed panels are then
either off-loaded by crane or slid into place once excavation of
the crossing is performed. Where adjacent ROW is available,
completed panels several hundred feet in length can be installed if
sufficient equipment is available. Pre-paneling helps minimize the
disruption to the public and to rail traffic.
Prior to removal of the crossing surface material, the appropriate
crossing permits must be secured from the local authorities,
highway traffic detours arranged, a work window obtained from the
railway’s Transportation Department and the appropriate detour
signage and barricades placed.
Pneumatic or hydraulic impact tools are required to remove threaded
lags in timber, rubber or concrete cast panel crossing materials.
The existing track is then cut into convenient panel lengths,
typically 39’, and lifted out by a crane – if tie condition is
adequate to hold rail in place while the panel is lifted. With the
trackbed exposed, excavation can begin. It is important that the
graded surface be level and no more than 10” be removed below
bottom of tie. At all costs, avoid excavating beyond the hardpan
that has formed from years of consolidation from train traffic. The
use of small tilt-blade dozers or comparable equipment is effective
in holding a level grade. Other suitable pieces of equipment for
removing and loading spoil from the immediate crossing site are
also required. The crossing panels are either slid in or placed by
a crane depending on the length and adjacent available ROW.
Once the panel ends are connected to the existing track, ballast is
dumped either by ballast cars or via loaders. The track panels are
then raised by the use of jacks to permit machine tamping and
raising of the crossing to grade. Additional ballast is dumped and
final surfacing and regulating is performed. Additional surfacing
will often be required after train operation until all settlement
is complete. The appropriate surface material is then
applied.
COPYRIGHT © AREMA 2010
12: * of 55
*
We now move to the activities beyond the scope of normal or routine
maintenance.
This includes production work such as production surfacing,
production relay of CWR, production tie insertion, and production
undercutting. Each of these activities is designed to maximize
productivity within the track windows present. The cost of these
functions is beyond the capability of a supervisor’s normal budget
and manpower consists. Extra gangs are created that often move from
territory to territory even division to division performing
specialized tasks. The accumulated experience obtained doing just
one task makes these gangs very efficient and productive. These
gangs are essentially rolling assembly lines that requires each
segment to perform its task safely and efficiently to keep the
entire process going.
The other engineering activity that occurs is the construction of
new track for capacity improvements or to accommodate changing
traffic patterns. The design engineering and construction project
management for these activities are typically performed by
consultants. In most cases, railways do not have sufficient staff
personnel to devote to these additional activities.
If local labor agreements permit, railways may even contract out
the construction of the trackage to outside contractors who are
equipped to do such projects. Grading and roadbed construction are
almost exclusively handled by contractors as most railways do not
possess the equipment required to perform this work. Installation
of the ballast section is usually done by the railway as the
railway possesses the required ballast hoppers.
COPYRIGHT © AREMA 2010
12: * of 55
*
The first production gang to be considered is the rail gang. Rail
renewal is determined chiefly by the condition of the existing
rail. Rail with significant secondary batter, chipped ends, bent
joints, corrugations too deep to grind out or with excessive curve
wear becomes impossible to maintain surface and speed restrictions
have to be imposed. Rail segments that have had a history of recent
failures, whether discovered ultrasonically or as outright broken
rail are placed for special priority. Older jointed rail, within
acceptable wear limits and that has been work-hardened by tonnage
prior to the inception of 100-ton cars, is rail that can often be
utilized for relay purposes. By cutting off 18" or more from each
end, the bolt holes are eliminated and the rail can be welded into
lengths of up to 1440 or 1600 foot long strings. This cascading
effect generates a significant amount of the rail laid in North
America – particularly on medium tonnage and secondary lines. Rail
may be re-laid out-of-face for relay of existing rail or can
involve the transposition of the high rail to the low rail and
vice-versa in curves – a practice called transposing rail.
Rail gangs will typically range from 30 to 60 men in size with 10
to over 20 machines. As such, they are the most labor-intensive
work function utilized. Expansion of the rail and installation at
gage are the primary performance criteria that must be considered
when laying jointed or continuous welded rail (CWR). CWR is laid at
a Preferred Rail Laying Temperature (PRLT), which will be the
rail's neutral temperature after anchoring and is designated per
geographic location by the railway. The neutral temperature favors
the higher range of expected rail temperatures, as a sun kink is
typically more dangerous than a pull-apart. If necessary, the rail
is artificially heated or cooled or adjusted hydraulically to a
corresponding length in order that it is within an acceptable
neutral temperature range. The rail is then anchored per railway
standard in order to lock in the neutral temperature.
The entire work process starts with the unloading of the CWR which
is welded at a rail plants and transported in special trains with
strings usually around 1440’ long. Unloading the rail is a
complicated and dangerous process that requires careful planning
and preparation with close attention paid to turnouts, road
crossings and bridge locations.
COPYRIGHT © AREMA 2010
12: * of 55
Rail Gang Make-up
*
Thread new rail to center of track - The first operation in the
rail gang is the threading of the new rail from the shoulder into
the center of the track ball up. Once the string is installed in
the center of the track, the primary functions may begin.
Remove spikes - Automatic spike pullers pull most of the spikes
with the remainder removed manually.
Remove anchors – The rail anchors are then removed either manually
or by machine.
Thread old rail out - A rubber tired speed-swing or Galion Crane is
used move the old rail from the tie plates out to the shoulder of
the track.
Remove tie plates - Existing tie plates are removed. Depending on
their condition or type they may be re-used or placed to the side
for pick up as scrap.
Plug spike holes in ties - Spike holes in the ties are either
manually filled with a wood plug or injected with an epoxy based
filler compound.
Crib - A crawler based machine called a cribber sweeps the ballast
out between the cribs with steel cable brushes to a depth that will
permit machine installation of the new anchors.
Adze - A machine called an adzer then planes the top of the tie
down to a smooth surface that will accept the new tie plate.
Replace tie plates - The next operation involves the setting of the
tie plates into place with a pregager that provides a positive stop
for the end of the plate
Thread new rail in - A speedswing or pettibone hi-rail equipped
crane threads the new rail into place into the plates – the machine
hi-rail wheels serving to seat and locate the rail.
Gage - This is followed by several automatic spikers, the first of
which is equipped with an automatic gaging feature to ensure that
the new rail is laid to gage based not on a ball to ball dimension
(56-1/2”), but a base to base dimension that will ensure the rail
will be to the proper gage once the first train properly seats the
rail into the plates.
Heat - With completion of the gage spiking operation, the rail is
heated with a diesel fuel or propane heater to a temperature
slightly in excess of the desired neutral temperature. The rail has
been pre-marked for the quarter, half and ¾ points on the string.
The tie plate and rail base is match-marked at these locations.
Once heating of the string begins, the required expansion is
calculated and at each of these points the match-mark offset is
compared against the calculated amounts to ensure that expansion is
actually occurring.
Anchor - Immediately behind the rail heater, are a fleet of
automatic anchor machines which apply the anchors to ensure that
the expanded rail is locked into place. Should the rail temperature
rise above the desired preferred rail laying temperature, the
heater is shut off and the rail temperature becomes the new neutral
temperature.
Spike - The automatic spikers are set up so that both inside and
outside gage spikes can be driven simultaneously. It takes skill to
rapidly locate the spike gun over the hole with the joystick
controls. Once the hydraulic action is initiated, it can’t be
stopped. A mislocated hole placement will result in a bent spike
and potential gang delay down the line.
Pick up scrap and old rail – Burro cranes, specialized scrap
retrievers, etc. are used to clean the right-of-way of the scrap
material to ready the track for surfacing. This keeps the property
clean, safe and the scrap metals are sold to help fund the
projects.
Surface track - A ballast regulator fills in the ballast cribs
followed by the surfacing gang and welders.
COPYRIGHT © AREMA 2010
12: * of 55
Production Tie Renewal
6 to 20 machines
October 2007
*
Tie renewal is typically scheduled ahead of rail relays to meet
minimum FRA standards or to fit within cycle based programs. Tie
life is a function of tonnage, topography and climate. For medium
and light tonnage lines in a dry and relatively flat territory, a
tie life of approximately 25 to 30 years is realistic except under
joints or crossings. On heavy-haul – high tonnage lines, a tie life
of 15 to 20 years is more realistic with wet climates and high
curvature territories averaging closer to the 15 year life. Tie
gangs will range from mini-gangs of 12 – 15 personnel to 30 to 35
men for high production units. Production may range from 500 ties
per day installed for a mini-gang to an average of 2500 ties per
day for a typical tie gang. Tie renewal is scheduled on a cycle
basis with anywhere from 400 to 1500 ties per mile replaced out of
approximately 3200 ties per mile. The intent is to keep all the
ties from requiring replacement at one time – a staggering cash
flow expenditure.
The typical tie gang is made up of two sections: the head end and
the hind end. Sequence of operations will vary by railroad and
differs somewhat for concrete tie installation, but in general
follows accepted practices.
The first step is distributing the new material. The top picture
shows a car topper unloading and spotting the ties to be inserted
along the right of way.
COPYRIGHT © AREMA 2010
12: * of 55
Tie Gang Make-up
*
The next step in the process is pulling the spikes and spreading
the anchors as shown in the top left picture. The TKO or tie
inserting machines can remove the old ties from the track. (Bottom
left). Each tie gang has several tie cranes that handle either old
or new ties (top right). One tie crane may pile up the old ties out
of the way to be picked up later while another crane will spot the
new tie in the hole left by the old tie.
Once the ties have been spotted by the tie cranes, the inserter can
shove them under the track in the hole left by the old tie. The
plates are replaced between the new tie and the rail, and then the
spikes are driven as shown in the bottom right photo and the
anchors squeezed tight to the tie.
COPYRIGHT © AREMA 2010
12: * of 55
Mechanized Tie Gang
COPYRIGHT © AREMA 2010
12: * of 55
*
Surfacing refers to the operation, whereby the alignment and
surface of the track are restored to within acceptable maintenance
limits and the ballast is tamped underneath the ties. It can be
classified as "spot" which is the localized repair to isolated
locations often done through the use of jacks and ballast forks or
shovels, or through the mechanized use of tampers, which is often
referred to as smoothing. Production surfacing includes skin lifts,
whereby low spots are corrected and the entire track structure is
given a skin lift of under an inch to full out-of-face surfacing,
whereby the track is raised 2 to 3" in a single pass, as would
occur under undercutting operations or at road crossing renewals.
Larger out-of-face lifts are ballast sensitive and sufficient
ballast must be on hand.
It is interesting to note that in an article from the 1934
Roadmasters Maintenance of Way Association Annual Proceedings,
William Shea, General Roadmaster of the Milwaukee, St. Paul &
Pacific Railroad, bragged about his high speed surfacing and lining
gang that could surface a mile per day. It consisted of 300 men
tamping and raising the track, 100 men lining the track and 100 men
following up two weeks later as a touch-up gang. Today with a
foreman, 4 – 5 machine operators and possibly 2 laborer, 2-1/2 or
more miles can be surfaced with a far greater degree of quality in
the work performed. Indeed today, there are machines that combine
all of the operations noted above in the typical surfacing gang
into one machine, which can travel out to the work site at near
train speeds.
COPYRIGHT © AREMA 2010
12: * of 55
Surfacing Gang Consist
Dynamic Track Stabilizer
*
Today's modern production tamper (CAT-09, continuous action tamper
– machine does not stop but tamping head moves independently from
tie to tie, MK IV – Harsco Company production/switch tamper), not
only can tamp the ballast under the tie with vibrating tools that
are inserted to either side of the tie and drop below the tie,
where they perform a squeezing operation that compacts the ballast
underneath, but are also equipped with jacks that can lift the rail
vertically at the point of tamping. They also can move the rail
horizontally for lining the track. Both vertical and horizontal
jacking are controlled by projecting an infra-red light from a
buggy set ahead of the machine (top left), which sends a light beam
back to a receiver located at the rear of the machine.
Other machines included within the surfacing gang may include a
tamper not equipped with jacks, that tamps every other tie behind
the production tamper, thereby increasing hourly production rates.
One or more ballast regulators (top right) are used to transfer or
recover ballast where needed for tamping or filling the cribs and
shoulders. The regulator is equipped with a power broom that sweeps
excess ballast off the top of tie and provides that “completed”
look. The surfacing gang may include a dynamic stabilizer (bottom
left). This machine imparts vibrations of a given frequency into
the rail to secure consolidation of the ballast structure. This
restores lateral stability after the track disturbance created by
surfacing and minimizes the placement of necessary slow
orders.
Adequate ballast must be dumped ahead of the gang to ensure that
cribs are not left empty and proper shoulders provided after
surfacing.
COPYRIGHT © AREMA 2010
12: * of 55
*
Undercutting, shoulder cleaning, sledding, plowing or track removal
with open cut excavations is performed whenever the ballast section
becomes so fouled with mud that line and surface can no longer be
maintained, or overhead clearances are so tight that track raising
is unacceptable. Undercutting production is generally limited by
availability of ballast and the amount of hard packed mud present
in the track. Typically, this will require 40 - 50 cars of ballast
per mile of track assuming that 6” to 8" of ballast is removed from
the bottom of the tie. The amount of ballast re-claimed will vary
depending on the type of ballast in place and its condition. The
dirt removed from the track is either wasted off on the ROW or
loaded by conveyors into air dump cars. It is important that spoils
wasted are bladed off so that a ridge trapping water is not
created. A tie gang should be operated through the track segment
prior to undercutting so that down-ties will be a minimum.
Undercutting operations also vary widely in set-up. However, the
key component is the undercutter. This machine has a large chain
with cutting teeth ( photo lower left) that is pivoted under the
ties at the required depth to be undercut until the chain is
perpendicular to the rail. As the chain rotates, the machine is
moved forward. A large vertical rotating wheel equipped with
buckets ( photo upper right) is mounted on the side of the machine.
The buckets first create space at the end of the tie from which the
chain can operate. The chain brings the material to the rotating
buckets, whereby the ballast is carried upward and dumped onto
vibrating screens (photo upper left). The dirt and smaller ballast
fines drop through and are deposited onto a conveyor that wastes
the material onto the ROW (photo upper right) or into an air dump
car. The larger ballast is returned to the track.
Smaller, less productive undercutters are used for switch
undercutting and even smaller units, called gophers, waste all
material and are ideal for spot undercutting through bridges,
platforms, etc.
COPYRIGHT © AREMA 2010
12: * of 55
Authors: Joseph E. Riley, P.E. Federal Railroad Administration
(202) 493-6357
[email protected]
Larry Romaine Rail America (904) 538-6054
[email protected]
Gray Chandler CSX (Retired) (904) 213-1121
[email protected]
October 2007
Romaine & Chandler
R. D. Kimicata
Art Charrow
J.G. Chandler
Charley Chamber
J.G. Chandler
Charley Chamber
J.G. Chandler
Mike McGinley
J.G. Chandler
5/16/2008ALLReverted format from PPTM to PPTR. D. Kimicata
1/28/201042Changed rail grinding picture and notesArt CharrowJ.G.
Chandler
1/28/201045-47, 49, 50, 52change titles from "Team" to
"Gang"Charley ChamberJ.G. Chandler
1/28/201050Added mechanized tie gang slideCharley ChamberJ.G.
Chandler
1/30/201025Changed picture of Sperry carMike McGinleyJ.G.
Chandler
7/25/201255Updated authors' informationJohn GreenN/A