Upload
others
View
3
Download
0
Embed Size (px)
Citation preview
MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Robert Netopilik, P.Eng., M.A.Sc.
Manager, Track Infrastructure
Metrolinx
Christopher Price, P.Eng.
Track and Civil Engineer
AECOM
IS EVERYONE WORKING TOGETHER?
2MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Track design
Foundation design
htt
ps:
//w
ww
.pin
tere
st.n
z/p
in/2
40
09
82
23
85
92
82
64
2/
INTRODUCTION
3MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
โช Desire to increase operating speed
โช 80 mph passenger, 60 mph freight
โช Limited space available
INTRODUCTION
4MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
โช Maximum passenger unbalance of 3.0โ
โช Cross-level construction tolerance of ยผโ
Degree of curve 1ยฐ30โ
Super-elevation 3.75โ
Passenger
Unbalance2.97โ
Passenger Speed 80 mph
Freight Unbalance 0.03โ
Freight Speed 60 mph
PROBLEM
5MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Design Constructed
Degree of curve 1ยฐ30โ 1ยฐ30โ
Super-elevation 3.75โ 3.50โ
Passenger Unbalance 2.97โ 3.00โ
Passenger Speed 80 mph 78.5 mph
Freight Unbalance 0.03โ 0.28โ
Freight Speed 60 mph 60 mph
โช The curve was constructed ยผโ under
the design super-elevation
โช The original design followed all
recommended methods
โช Verification with a geometry car
revealed a maximum speed of 78.5
mph
โช A TSO was required
โช This location will always be
susceptible to cross-level error
So what happened?
FUNDAMENTALS OF CURVE DESIGN
6MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
โช Balanced super-elevation is the point at
which the force on both of the rails is
the same
โช Balanced Super-elevation is calculated
using the formula:
โช The balanced super-elevation can be
related to the actual and the
unbalanced super-elevation through
the following formula:
E๐ = 0.0007 ๐ฅ ๐ท๐ ๐ฅ ๐2
๐ธ๐ต = ๐ธ๐ด + ๐ธ๐
EA = EB
Eu = 0
Eu > 0
Underbalanced
Centrifugal Force
Weig
ht
Eu < 0
Overbalanced
FUNDAMENTALS OF CURVE DESIGN
7MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Centrifugal Force
Weig
ht
โช Occurs when the
unbalance is less than 0
โช There is too much super-
elevation applied
โช Low rail plastic
deformation
โช Increased gauge widening
lateral loads
โช Increased maintenance
intervals required
โช This is not a desired case
โช Occurs when the
unbalance is greater than 0
โช There is not enough super-
elevation applied
โช Limited by passenger
comfort
โช Regulatory limits that
cannot be exceeded
โช Results in high rail gauge
corner wear
โช Is considered more
desirable
Eu < 0
OverbalancedEu > 0
Underbalanced
CONSTRUCTION AND MAINTENANCE TOLERANCES
8MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Track Class 1 2 3 4 5
Speed 15/10 30/25 60/40 80/60 95/80
Priority 1โ 1โ ยพโ ยฝโ ยฝโ
Urgent 3โ 2โ 1-ยพโ 1-ยผโ 1โ
Maintenance is governed by two key areas:
1. Cross-level deviation from design
โช Defects are โpriorityโ or โurgentโ
โช Allows for maintenance measures before
introduction of a TSO
โช Avoids the reduction in track speed
CONSTRUCTION AND MAINTENANCE TOLERANCES
9MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Maintenance is governed by two key areas:
2. Vmax
โช The balanced super-elevation formula
is rearranged to yield maximum
allowable speed
โช This formula has been adopted by both
TC and FRA as a regulatory limit
๐๐๐ด๐ =๐ธ๐ด + ๐ธ๐ข0.0007 ๐ท๐ถ
Construction is governed by:
1. Cross-level deviation from design
โช Typically varies by agency
โช ยฑยผโ is a common value
CONSTRUCTION AND MAINTENANCE TOLERANCES
10MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Applying these two cases to the previous example:
โช Passenger speed 80 mph,
freight speed 60 mph
โช Class 4 track
โช Degree of curvature is 1ยฐ30โand maximum unbalance is
3.0โ
โช Priority defect: ยฝโ
โช Urgent defect: 1-ยผโ
Criteria 1
Cross-level from
design
Design 3.75โ
Construction
Tolerance3.50โ
Priority Defect 3.25โ
Urgent Defect 2.50โ
Maintenance action triggered
No reduction in speed required
CONSTRUCTION AND MAINTENANCE TOLERANCES
11MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
Applying these two cases to the previous example:
Criteria 1
Cross-level from
design
Design 3.75โ
Construction
Tolerance3.50โ
Priority Defect 3.25โ
Urgent Defect 2.50โ
Maintenance
action triggered
No reduction in
speed required
Criteria 2
๐๐๐ด๐
80 mph
79 mph
77 mph
72 mph
Maintenance
action triggered
Reduction in
speed required
CAUSE
12MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
โช Design speed close to the regulatory
limits causes issues after construction
โช Bypasses the priority and urgent
defect classification
โช Standards do not incorporate any
tolerances in the design
Current industry standard is to โavoid the
unbalance limitsโ, but how can this be
quantified?
UNBALANCE UPPER LIMITS
13MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
โช The upper limits in the
field are defined by
regulatory bodies
โช Adding a maintenance
buffer ๐๐ต reduces the
likelihood of early
intervention
โช This reduces the
maximum allowable
unbalance in design
๐๐๐ด๐ =๐ธ๐ด + ๐ธ๐ข0.0007 ๐ท๐ถ
In the field...
๐๐๐ด๐,๐ท๐ธ๐๐ =๐ธ๐ด,๐ท๐ธ๐๐ + ๐ธ๐,๐๐ด๐ โ ๐๐ต,๐๐ด๐
0.0007๐ท๐ถ
In Design...
๐๐ต,๐๐ด๐ Desired = ยฝโ
๐๐ต,๐๐ด๐ Absolute = ยผโ
Assumed construction cross-level tolerance of ยผโ
UNBALANCE UPPER LIMITS
14MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
๐๐๐ด๐ =๐ธ๐ด + ๐ธ๐ข0.0007 ๐ท๐ถ
In the field...
๐๐๐ด๐,๐ท๐ธ๐๐ =๐ธ๐ด,๐ท๐ธ๐๐ + ๐ธ๐,๐๐ด๐ โ ๐๐ต,๐๐ด๐
0.0007๐ท๐ถ
In Design...
๐๐๐ด๐
Speed
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐,๐ท๐ธ๐๐Desired
UNBALANCE LOWER LIMITS
15MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
โช There are no regulatory
requirements for the
minimum unbalance
โช Itโs generally common
practice to avoid
negatives
โช Desired case of zero
unbalance
โช Absolute case of -1โ
unbalance
In the field...
In Design...
๐๐ต,๐๐ผ๐ Desired = ยผโ
๐๐ต,๐๐ผ๐ Absolute = -ยพโ
๐๐๐ผ๐,๐ท๐ธ๐๐ =๐ธ๐ด,๐ท๐ธ๐๐ + ๐๐ต,๐๐ผ๐
0.0007๐ท๐ถ๐๐๐ผ๐ =
Assumed construction cross-level tolerance of ยผโ
Not
Defined
UNBALANCE LOWER LIMITS
16MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
๐๐๐ด๐
Speed
In the field...
๐๐๐ผ๐ =๐ธ๐ด + ๐ธ๐ข
0.0007 ๐ฅ ๐ท๐ถ
Not
Defined
In Design...
๐๐๐ผ๐,๐ท๐ธ๐๐ =๐ธ๐ด,๐ท๐ธ๐๐ + ๐๐ต,๐๐ผ๐
0.0007๐ท๐ถ
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐,๐ท๐ธ๐๐Desired
SOLUTION
17MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
๐๐๐ด๐
Speed
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
๐๐ต,๐๐ผ๐ Desired = ยผโ
๐๐ต,๐๐ผ๐ Absolute = -ยพโ
๐๐๐ผ๐,๐ท๐ธ๐๐ =๐ธ๐ด,๐ท๐ธ๐๐ + ๐๐ต,๐๐ผ๐
0.0007๐ท๐ถ๐๐๐ด๐,๐ท๐ธ๐๐ =
๐ธ๐ด,๐ท๐ธ๐๐ + ๐ธ๐,๐๐ด๐ โ ๐๐ต,๐๐ด๐
0.0007๐ท๐ถ
๐๐ต,๐๐ด๐ Desired = ยฝโ
๐๐ต,๐๐ด๐ Absolute = ยผโ
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐,๐ท๐ธ๐๐Desired
DESIGN LIMITS
18MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐
๐๐๐ด๐,๐ท๐ธ๐๐Desired
Speed
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
Applying these to the previous example:
53.5 mph 61.7 mph 77.2 mph 78.7 mph
80.2 mph
FreightSpeed
PassengerSpeed
Exceeds desired
limits but not
absolute
Absolute limits
exceeded
What if we adjust the super-elevation?
19MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐
๐๐๐ด๐,๐ท๐ธ๐๐Desired
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
53.5 mph 61.7 mph 77.2 mph 78.7 mph
80.2 mph
๐๐๐ด๐
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
63.6 mph
๐๐๐ด๐,๐ท๐ธ๐๐Desired
78.7 mph
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
80.2 mph
81.5 mph
Ea = 3.75โ
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
55.6 mph
FreightSpeed
PassengerSpeed
Exceeds desired
limits but not absolute Exceeds desired limits
but not absolute
Ea = 4.00โ
DESIGN LIMITS
20MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐
๐๐๐ด๐,๐ท๐ธ๐๐Desired
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
53.5 mph 61.7 mph 77.2 mph 78.7 mph
80.2 mph
Ea = 3.75โ
Ea = 4.00โ
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐
๐๐๐ด๐,๐ท๐ธ๐๐Desired
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
57.7 mph 65.5 mph 80.2 mph 81.7 mph
83.1 mph
Ea = 4.25โ
Exceeds desired
limits but not absolute Does not exceed
desired limits
DESIGN LIMITS
21MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00
Super-
ele
vation (
Inches)
Speed (mph)
Ea = 4.25โ
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
๐๐๐ด๐,๐ท๐ธ๐๐Desired
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐Absolute
๐๐๐ด๐ Plots for 1ยฐ30โ Curve
GRAPHICAL REPRESENTATION
Ea = 3.75โ
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
20.00 30.00 40.00 50.00 60.00 70.00 80.00 90.00 100.00
Super-
ele
vation (
Inches)
Speed (mph)
22MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
GRAPHICAL REPRESENTATION
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
๐๐๐ด๐,๐ท๐ธ๐๐Desired
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐Absolute
๐๐๐ด๐ Plots for 2ยฐ00โ Curve
Ea = 4.25โ
SOLUTION
23MIXED-USE CORRIDORS: DESIGN MEETING STANDARDS RESULTING IN TRACK DEFECTS
๐๐๐ด๐
Speed
๐๐๐ผ๐,๐ท๐ธ๐๐Absolute
๐๐๐ผ๐,๐ท๐ธ๐๐Desired
๐๐ต,๐๐ผ๐ Desired = ยผโ
๐๐ต,๐๐ผ๐ Absolute = -ยพโ
๐๐๐ผ๐,๐ท๐ธ๐๐ =๐ธ๐ด,๐ท๐ธ๐๐ + ๐๐ต,๐๐ผ๐
0.0007๐ท๐ถ
๐๐๐ด๐,๐ท๐ธ๐๐ =๐ธ๐ด,๐ท๐ธ๐๐ + ๐ธ๐,๐๐ด๐ โ ๐๐ต,๐๐ด๐
0.0007๐ท๐ถ
๐๐ต,๐๐ด๐ Desired = ยฝโ
๐๐ต,๐๐ด๐ Absolute = ยผโ
๐๐๐ด๐,๐ท๐ธ๐๐Absolute
๐๐๐ด๐,๐ท๐ธ๐๐Desired
โช Overbalanced case requires more
maintenance and is not desired
โช Regulatory limits on the allowable
underbalance
โช Common practice is to avoid the
unbalance limits
โช Vmax defects do not follow priority
and urgent defect types and require
immediate intervention
โช Proposed formulas place design
limits below the regulatory limits
QUESTIONS?
Robert Netopilik, P.Eng., M.A.Sc.
Manager, Track Infrastructure
Metrolinx
Christopher Price, P.Eng.
Track and Civil Engineer
AECOM