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592

LRT systems compared to rubber-tired AGT systems have the following advantages (+) and disadvantages (-): + LRT is not limited to ROW A only; it can utilize ROW categories B and C also. + LRT can fit into urban and pedestrian zones and enhance their environment. + LRT requires much lower (two to three times) investment cost per km of line than AGT. + Rail vehicles offer considerably better riding comfort than two-axle rubber-tired guided vehicles. + LRT has a good image and is very popular as a symbol of the city. + Rail systems are generic, produced competitively by many manufacturers; AGT modes are proprietary,

produced by one supplier only. — LRT cannot be operated automatically, unless it has only ROW A. — LRT has lower speed and much lower frequency of service than AGT. — LRT has somewhat lower safety than AGT. — LRT schedules cannot be as quickly adjusted to unexpected changes as AGT schedules.

lower investment cost and greater physical ability to fit into a urban environment without either tunneling or using aerial structures that are not acceptable in high-density areas. In many Asian cities, particularly in Japan and Singapore, AGTs have prevailed when large funds were made available and cities are not so envi-ronmentally sensitive that aerial structures would be objectionable. Overall, LRT systems are used in many more cities and have much more extensive networks than AGT systems.

12.3 HIGH-PERFORMANCE TRANSIT MODES

The basic feature for provision of high-performance transit service is operation on ROW category A only. With exclusive use of protected ROW, guided modes represent the logical technology because guidance al-lows use of high-capacity electric trains with signal control. By far the most dominant modes in this cat-egory are rail rapid transit and regional rail systems. This section will, however, include several other high-performance modes, starting with LRRT operating ex-clusively on ROW A and moving to rubber-tired rapid

transit and monorails and finally to the highest-performance mode, regional rapid transit.

12.3.1 Light Rail Rapid Transit (LRRT) Modes

This group of modes includes systems that have modified LRT rolling stock operating on alignments with ROW category A over their entire length. When these LRT trains are operated by drivers, the mode is known as light rail rapid transit (LRRT). The same mode but with fully automated operation is known as automated (or advanced) light rail transit (ALRT). The fact that it is automated indicates that this system has only ROW A, i.e., it actually represents an automated LRRT.

12.3.1.1 Light Rail Rapid Transit. Rolling stock of this mode has several differences from regular LRT stock. LRRT stations usually have high platforms and cars with several doors for fast passenger boarding and alighting. The trains have high operating speed and fail-safe signalization, the same as metro systems.

12.3 HIGH-PERFORMANCE TRANSIT MODES

Thus, LRRT can be considered the highest type of LRT, or a smaller-scale "mini-metro."

There are not many LRRT systems because in most cases transit lines are built with ROW A when there are large passenger volumes, and in such cases long trains and other metro features are needed. Only in special cases is this highest type of ROW provided for lines that carry only moderate passenger volumes. Ex-amples of this mode include the Norristown Line in the Philadelphia suburbs, line 8 in Goteborg, Sweden, and several recently built fully separated LRT lines, such as those in Los Angeles, Manila, the Philippines, and Frankfurt and Essen-Miilheim, Germany.

With the increasing demand for high-quality transit services, increasing use of the LRRT mode is likely in the future. Conversion of commuter railway lines to

this mode, to achieve considerably lower operating costs and better level of service, is a logical develop-ment in many cities.

12.3.1.2 Automated Light Rail Transit. This mode is a fully automated version of LRRT, or it may be considered an AGT system with rail technology. It involves higher investment cost than LRRT because of automation and certain operational provisions that such operation necessitates (platform supervision, detection of objects fallen on track, emergency procedures, etc.), but its operating costs are lower, even for operation with shorter headways than LRRT, because they do not involve driver's wages. Without train crews, operating cost of, for example, four single-car trains is the same as that of one four-car train (at four times longer head-

Photo 12.13 Light rail rapid transit (Green Line) in Los Angeles.

PLANNING AND SELECTION OF MEDIUM- AND HIGH-PERFORMANCE TRANSIT MODES

594

RRT/metro compared to LRT has the following advantages (+) and disadvantages (—):

+ With ROW A only and full signal control, RRT has higher speed, reliability, and safety. + Due to long trains and rapid passenger exchange at stations, RRT has much higher line capacity. + With its high performance and strong image, RRT has stronger passenger attraction. + Distinct image of its stations and system permanence give RRT greater potential for positive impacts on urban development than any other transit mode. — RRT requires substantially higher investment cost, causes more disruption due to construction, and

requires longer implementation time than LRT. — RRT requires more rigid alignment than LRT and cannot penetrate pedestrian areas. — LRT is more conducive to construction in stages, utilizing different ROW categories, while RRT is

limited to ROW A only.

ways). The other benefits of full automation, discussed in Section 12.1.2.4, also apply in this case.

The ALRT system, opened in Vancouver in 1986 and named Skytrain, is the best-known example of this mode. Operating up to four-car trains at headways as short as 2.5 minutes, the theoretical capacity of the Skytrain reaches 28,860 sps/h, considerably greater than the capacities of rubber-tired ACT systems. The Skytrain has propulsion by linear-induction motor, but that feature is independent of the basic system concept. The same type of ALRT with conventional electric motor propulsion is used on Detroit's Downtown People Mover, a collector-distributor loop in the CBD.

Another major ALRT system is the London Dock-lands system, a line planned and built as a part of a major urban development. It has been subsequently ex-panded into a network. The Docklands Line has an attendant on each train, but it can still be considered ALRT because driving is automatic and the attendant is on the train to assist passengers with information and fares. In 2003, another ALRT was opened in Co-penhagen.

ALRT is a mode that will have increasing impor-tance in the future because technical and operational problems of automatic driving have been solved and tested, and high quality of service (mainly short head-ways) is increasingly important for passenger attraction on all high-performance transit systems.

12.3.2 Rail Rapid Transit (Metro)

Rail rapid transit (RRT), popularly better known as metro, utilizes high-capacity electric trains with high acceleration and braking rates. It represents the highest-performance transit mode with the lowest operating cost per space-km. Its implementation requires very high investment and extensive construction, including disruption of areas along future lines. However, RRT systems have virtually unlimited life and exert a strong, permanent impact on mobility of population, urban form, and character.

A comparison of RRT with its closest widely used neighbor in the family of modes, standard LRT, is pre-sented in the box.

This comparison shows that RRT has a significantly higher PCP than LRT. RRT actually represents the highest-performance transit mode that requires the highest investment and has the most permanent positive impacts on the city and region. The differences in these features between typical RRT systems and typical systems of other modes are considerable, but variations in designs of different modes have shown that LRT and regional rail systems can be designed to such high standards that they approach rapid transit in their characteristics. As already mentioned, the innovations in transit system designs in recent decades have created a nearly continuous family of transit modes. This is

12.3 HIGH-PERFORMANCE TRANSIT MODES 595

particularly the case among rail and other guided transit modes.

Growth of cities, increasing demand for travel, and the growing need for high-performance transit that is independent of frequently congested urban streets have resulted in construction of metros in a large number of cities during recent decades. In 1950, only 17 cities in the world had metros; in 2005, that number exceeds 100 cities.

The dominant reason for building many metro sys-tems is provision of high transporting capacity in major urban corridors and arterials. In an increasing number of cities, however, metros are being built not only for greater capacity, but for provision of high-quality ser-vice. The reasons for these objectives are the growing expectations of high-quality transit services and the need for such services to attract urban travelers from their automobiles. Improved mobility, intensified eco-nomic activities, and enhanced urban livability are, of course, additional factors leading to investment and ef-forts to build metro systems.

Sometimes considered a fixed concept, RRT sys-tems actually have a broad range of variations in their physical and operational features. Several features with their variations are described here.

With respect to ROW types, RRT systems usually have tunnel alignments in large central city areas, such as in New York, Paris, and Tokyo. The underground operation gives these systems a special image and often their names: "subway" in the United States; un-derground" in England, "U-Bahn" in Germany, and "T-Bana" in Sweden. However, RRT systems have very diverse rights-of-way: although always fully sep-arated, they can be at-grade, on embankment, on aerial viaduct, in a cut, or in tunnel. Actually, because tunnels require by far the highest investment of all alignment types, many RRT systems, including those in Chicago, Hamburg, London, and New York, have larger portions of their lines above ground than in tunnels. This diversity of ROW types shows the ability of RRT to have alignments adjusted to physical conditions, urban en-vironment, and financial resources.

By network extensiveness and station spacings (see Chapters 4 and 5), RRT systems vary from local metro lines in dense urban areas with close stations (Berlin,

Madrid, Paris, Philadelphia) to regional lines, which, similar to regional rail systems, have few stations and much higher operating speeds (San Francisco, Wash-ington).

Vehicles and train sizes also vary greatly. Lyon Metro has trains with only three 18-m-long cars, while San Francisco BART operates trains with up to ten 21-m-long cars. Thus, maximum TU lengths vary from 54 to 210 m. The shortest trains, operated during night hours on the PATCO Line in Philadelphia, consist of a single 21-m-long car.

Operating speeds of RRT go from about 30 km/h on short inner city lines with short station spacings to 60 km/h on regional metro lines such as San Francisco BART and Washington Metro, where on suburban sec-tions with long station spacings operating speeds may reach even 80 km/h.

Line capacities have a similarly wide range, from about 16,000 sps/h in Lyon to over 70,000 sps/h in New York and Hong Kong.

Construction cost depends mostly on vertical align-ment, as well as local conditions. In very general terms, the lowest investment is required for ground-level ROW, particularly if a transportation corridor al-ready exists (railway line, freeway median). Other ground-level alignments may cost considerably more. Aerial structures are two to four times more expensive to build than ground-level alignment tracks, while the ratio of average costs of tunnels is again two to three times higher than the average cost of aerials. Most of the costs for underground alignment go to station con-struction.

It should be mentioned that these investment costs for metro line construction must be weighed carefully not only against operational aspects of the lines (tun-nels have the advantage of total weather protection), but even more so against the desirability of alternative alignments. In many cases, the most direct alignments, serving areas of intensive activities, are the most ex-pensive to build, but they bring the highest permanent benefits to the riders and the city in general. On the other hand, the lowest-cost alignments may be the least desirable ones for rail transit passengers.

Good examples of this alignment desirability are transit alignments in freeway medians. Since freeway

PLANNING AND SELECTION OF MEDIUM- AND HIGH-PERFORMANCE TRANSIT MODES 596

Photo 12.14 Rail rapid transit being upgraded to full automation—Berlin.

alignments, if correctly planned, go around and be-tween areas of major activities (CBDs, suburban towns, etc.), by definition they do not follow corridors with heavy transit travel. RRT, to the contrary, should optimally follow major activity streets and boulevards and go into urban and suburban centers: it is a major element of their vitality and competitiveness with sub-urban sprawling, auto-based developments. The optimal alignments of the two therefore usually do not coincide. RRT can, however, effectively use medians on sections of radial freeways, then leave them to enter the high-density areas, usually in tunnels. Examples of such solutions are found in the San Francisco Bay Area (the Concord-Bay Point Line) and Chicago (the O'Hare Airport Line).

In conclusion, although RRT is a mode with exten-sive infrastructure, it provides many variations and dif-

ferent choices with respect to its ROW positions, types of stations, rolling stock, and performance to fit a variety of local conditions. The more than 100 rapid transit systems in the world illustrate a wide range of options that the designers of new rapid transit systems can use.

12.3.3 Rubber-Tired Rapid Transit (RTRT)

This is actually a metro system with a different support/guidance technology than rail. Its cars have trucks with four large rubber tires that carry the vehicle and four small tires that steer the truck, guided by lateral vertical surfaces. The trucks also have steel wheels that provide guidance through track switches and support the truck in the case of flat supporting rubber tire.

1Z.3 HIGH-PERFORMANCE TRANSIT MODES 597

The track consists of two paths (which may be wood, concrete, or steel) on which supporting tires run, two vertical guiding surfaces, and standard track with steel rails. Thus, RTRT represents a technical subalternative of the rail rapid transit mode.

Introduced in Paris in 1959, this technology was designed to reduce noise in metro tunnels, increase acceleration/deceleration, and enable operation with shorter headways, increasing line capacity. As tradi-tional rail rapid transit was modernized through welded rails, track construction preventing and absorbing noise, and new rolling stock designs, measurements have shown that most new rail systems are usually at least as quiet as RTRT systems. Acceleration and de-celeration rates are also similar on rail and rubber-tired systems because their maximum values are limited by the comfort and safety of standing passengers. With considerably more complex guidance mechanism and guideways and higher energy consumption and heat production, RTRT technology has been considered but not selected by most new rapid transit system designers for the reasons summarized in the box.

The transit agency in Paris, RATP, converted several of its Metro lines to RTRT technology but retained conventional rail technology on other lines. French de-signers have, however, prevailed with the selections of RTRT technology on several new metro systems they

designed and financed. At present, in addition to several metro lines in Paris, RTRT operates successfully on entire metro networks in Lyon and Marseilles, France; Montreal, Canada; Santiago, Chile; and, with a different design of guidance, in Sapporo, Japan. By far the largest metro system with rubber-tired technology is in Mexico City.

In the Mexico City application, however, some lim-itations of this technology are rather obvious. With small cars (15m long, 2.50 m wide) due to rubber-tire limited load capability, nine-car trains provide a ca-pacity of only about 35,000 prs/h, which is exceeded on several lines, causing serious congestion. The crowded conditions result in avoidance of the system by a considerable number of potential riders, particu-larly auto owners.

12.3.4 Monorails

Popularized by science-fiction writers many decades ago, monorails tend to enjoy the image of being the transit mode of the future. There are a number of mon-orail designs, starting from the classical and very popular Schwebebahn in Wuppertal, Germany (operating successfully since 1901) and including several other suspended and supported types. The most common

RTRT, compared with standard RRT technology, has the following advantages (+) and disadvantages (—):

+ Greater adhesion under normal (dry) conditions, allowing negotiation of steeper grades and use of trailers

+ Lower noise and vibration production in sharp curves = The same acceleration rates — Greater vulnerability to rain, snow, and ice conditions, limiting its applications to cities with a warm climate

or to tunnels only (Montreal) — Constraint on vehicle size due to the limited carrying capacity of rubber tires — Higher energy consumption, mainly due to greater rolling resistance — Higher heat production and fire hazard, requiring stronger ventilation and fire protection — Higher investment and operating costs because of greater technical complexity and higher energy

consumption

PLANNING AND SELECTION OF MEDIUM- AND HIGH-PERFORMANCE TRANSIT MODES 598

Photo 12.15 Rubber-tired metro—Paris.

monorails today are based on the Alweg design from the 1950s, with many improvements. Such monorails operate on long transit lines in Tokyo (from Hama-matsucho station in the city to Haneda Airport), the city of Kitakyushu on Kyushu Island, and several other Japanese cities. In Seattle, a short shuttle line has been in operation since the World's Fair in 1962 and is being replaced by a much longer line. A new line with the same technology has been opened in Las Vegas with the assistance of private capital, while Disneyland in California and Disney World in Florida have operated very popular smaller-scale monorails of the same tech-nology for several decades. More than a dozen mon-orails with different technologies, supported and suspended, are operated in other cities, mostly in Japan.

A serious disadvantage of monorails is the nature of their guideways and switches. Unlike rail systems, monorail beams cannot cross each other, and their switches are slow and take a large area, so that their yards and other maneuvering areas take large space. Another disadvantage is that they have much larger profile than rail and other guided modes, so that they are not conducive to tunnel operations. Their aerial structures, consisting of columns and guiding beams, are, however, smaller and less imposing on the sur-roundings than aerial structures of rail and AGT modes.

These characteristics make monorails more condu-cive to single lines than to networks. That is confirmed by the fact that all existing monorails consist of single lines; none of them represents a network. They are

12.3 HIGH-PERFORMANCE TRANSIT MODES 599

used mostly on wide streets and boulevards and in open areas, where tunneling is not required. The pres-ently designed new monorail line in Seattle will test the acceptability of aerial guideways in streets with high buildings and other urban settings.

In addition to their operational complexity and de-pendence on aerial alignments, monorails require in-vestment much higher than LRT requires, in the range of costs of RRT systems. For example, the Kitakyushu monorail in Japan and the Newark Airport and Las Vegas monorails required investments in the range of $85-125 M/km.

Thus, monorails represent a technological option for rapid transit lines, and in some cases they may represent an attractive solution. The factors favoring their applications include their exotic/novelty image, the need to follow horizontally and vertically curved alignments (the guideway does that efficiently, as dem-onstrated on the Tokyo-Haneda Line), and the need for minimum visual intrusion of aerial guideways along urban arterials. However, their technical characteristics present operational complexities. This is particularly the case in applications for networks of lines and align-ments in built-up urban areas and tunnels, where monorails are distinctly inferior to conventional rail systems, LRT, or RRT.

12.3.5 Review of Guided Modes and Their Automation

The preceding sections have shown that rail and other guided transit modes have a wide variety of charac-teristics. Classifications of modes by their ROW categories, types of vehicles and TUs, operational characteristics, and degrees of automation show various overlaps in many of these elements. To provide an overview of the modes with ROW A with emphasis on their technical characteristics, particularly guidance, propulsion, and automation, typical systems of different categories of high-performance modes with added AGT modes are listed in Table 12.9.

The sequence of these modes generally follows their historic evolution. As the table shows, there has

been an increase in automation, starting from AGT sys-tems as shuttles and then on several regular transit lines. At the same time, conventional rail systems began to apply ATO controlled by the driver, followed later by full automation without driver (first on ALRT, then on RRT).

A note of caution about transit system automatic operation is called for here. Fully automated train op-eration, without drivers, should be expected to be in-creasingly used. However, its advantages are more important on medium-capacity modes than on large rapid transit systems such as in New York, Hong Kong, and Mexico City, where presence of a person (driver or attendant) is desirable for many reasons, and the cost of an employee in a train carrying hundreds or thousands of passengers is easy to justify. Thus, fully automated train operation is not necessarily a desirable target for all rapid transit systems.

Progress toward full automation has had its suc-cesses as well as problems. Many AGT systems could not operate in any other way: automation makes their frequent service feasible. However, the designers of many of these systems have failed to use two main advantages of full automation: provision of high ser-vice frequency without increased operating cost, and tailoring TU size to demand to reduce operating costs. Only the Skytrain in Vancouver and a few other AGT systems use these advantages of automation. On the other hand, all AGT systems in Japan and automated metro systems in Paris and Singapore operate fixed TU consists, forgoing the main operational benefits of op-erations without crews. The future progress of auto-mation will depend on a more comprehensive systems approach that leads to better utilization of potential benefits from full guided transit automation.

12.3.6 Regional Transit Modes

As cities grow into metropolitan areas or urbanized regions, there is an increasing need to provide regional transit systems. These are characterized by long lines from the central urban area to suburbs and, in large metropolitan areas, among suburbs. Station spacings

Photo 12.16 Modem monorail system - Las Vegas (Courtesy of Bombardier Transportation).

12.3 HIGH-PERFORMANCE TRANSIT MODES 601

Table 12.9 Classification of RRT, ALRT, and AGT systems by design and operation with respect to automation Category

City

Support/ Guidance

Propulsion

Driving

Crews

Line Capacity

Conventional RRT

New York Subway Mexico City Metro

Rail RT

EM EM

M M

D+A D+A

Very high High

Upgraded conventional RRT

Hamburg U-Bahn Moscow Metropolitan

Rail Rail

EM EM

M, ATO M, ATO

D D, A

High Very high

Contemporary RRT (since 1970)

San Francisco BART Munich U-Bahn

Rail Rail

EM EM

ATO ATO

D D

Very high High

AGT (shuttles)

Atlanta (Hartsfield) Singapore MRT feeder

RTRT

EM EM

FA FA

N N

Medium Low

AGT (urban)

Lille VAL Taipei VAL

RT RT

EM EM

FA FA

N R

Low Medium

LRRT

Philadelphia (Norristown) Toronto (Scarborough)

Rail Rail

EM LIM

M ATO

D D

Low Low

ALRT

Vancouver London (Docklands)

Rail Rail

LIM EM

FA FA

N A

Medium Medium

Automated Metro/RRT

Lyon Metro Line D Paris Metro Line 14 Singapore-NE Line

RT RT Rail

EM EM EM

FA FA FA

N R N

Medium High High

RT: Rubber tired EM: Electric motor LIM: Linear induction motor M: Manual ATO: Automatic train operation FA: Fully automated D: Driver A: Attendant

R: Roving attendant N: No crews

are long, so that travel speed on regional network is considerably greater than on urban transit. Serving mostly long trips among areas and subcenters, regional transit is usually superimposed on regular transit that serves local travel within central city and suburban areas.

Regional transit services are provided by bus, LRT, and commuter/regional rail modes. Regional express buses, operating in mixed traffic or on special lanes, cannot be defined as high-performance modes because they perform commuter services only and their relia-bility is dependent on traffic conditions. Yet they are briefly included here because of their important role as

the only mode providing regional services in many cities.

12.3.6.1 Regional Express Buses. To provide re-gional service at speeds competitive with auto travel in U.S. metropolitan areas, buses usually must utilize major arterials and freeways. Most U.S. cities have more extensive freeway networks than their counterparts in other countries, and their express buses represent the most common, often the only, regional transit.

Typically, regional express buses run on streets in suburban areas, then get on a freeway for nonstop travel into center city, where they usually again get on

PLANNING AND SELECTION OF MEDIUM- AND HIGH-PERFORMANCE TRANSIT MODES 602

Photo 12.17 First fully automated rapid transit—Lyon Line D.

streets for distribution of passengers, transfers to other lines, etc. There are extensive networks of express bus lines utilizing HOV facilities in a number of cities, most notably Dallas, Denver, Houston, Los Angeles, Minneapolis, and Seattle. A large network of regional buses is operated also in the New Jersey suburbs of New York City, supplementing the NJT regional rail lines also serving that region. In New York City, these lines terminate in the Port Authority Terminal, the largest bus terminal in the world, with direct transfer to the subway lines. Similar networks terminate and have transfers to rail lines on the Manhattan side of the George Washington Bridge and in San Francisco in the Transbay Terminal.

Most regional bus lines in U.S. cities represent commuter transit rather than regular transit. They offer very limited, often no, services during off-peak peri-ods. Among the exceptions to this are three leading bus systems in North America: Ottawa, Pittsburgh, and

Portland. These systems are mentioned in Section 12.2.1.

12.3.6.2 Commuter Rail. In many cities around the world, railway lines going through suburbs and entering the city have been used for commuter trains, bringing mostly daily commuters into and out of the city. These lines typically terminate in stub stations on the fringes of central city. For example, London has about a dozen stations where commuter lines operated by British Rail and its successors terminate and connect with the Underground (RRT) lines. Commuter rail lines terminate in similar stub stations in Boston, Chi-cago, San Francisco, and Paris.

Commuter rail plays an extremely important role in bringing workers into large cities of both industrialized countries (Buenos Aires, Milan, Moscow, New York City, Osaka, Tokyo, etc.), as well as in developing

1Z.3 HIGH-PERFORMANCE TRANSIT MODES 603

Photo 12.18 Tokyo subway with linear induction motor.

countries (Bombay, Cape Town, Johannesburg, Sao Paulo, and many others).

Commuter rail systems in many cities represent by far the most efficient mode for bringing and returning extremely peaked loads of daily commuters from sub-urbs. They offer high speed, high comfort, and re-liability and provide high line capacities. Their disadvantages are that their headways are long and ir-regular, making their use in off-peak hours difficult or totally nonexistent. Moreover, in some cities the rail-way agency is not sufficiently interested in these ser-vices because its main focus is intercity passenger and freight trains. With the increasing demand for high-quality regional transit, the trend has been to upgrade commuter rail into regional rail lines or networks.

12.3.6.3 Regional Rail. These railway systems belong either to the railway or to the transit agency. They are specially designed as regional passenger rail net-

works, running through central city and providing better coverage than radial commuter lines, which serve only one or a few central stations. Moreover, the growth of polycentric urban areas with major activity centers in suburbs creates demand for high-performance transit networks that provide links among such suburban centers, rather than only radial lines to center city. These polycentric links are provided mostly by buses, but in several cities there is an increasing interest in upgrading such circumferential or tangential lines to rail systems. The highly successful link between Sacramento and San Jose in California is tangential to San Francisco, and similar lines are being considered in Chicago, Los Angeles, and Philadelphia. Typical regional rail modes are the S-Bahn systems in Berlin and Hamburg, JR lines in Tokyo and other Japanese cities, and RER in Paris. With electric traction, lines through central cities with many stations, and operation with short headways, they are more sim-

PLANNING AND SELECTION OF MEDIUM- AND HIGH-PERFORMANCE TRANSIT MODES 604

Photo 12.19 Push-pull diesel commuter rail service—Toronto.

ilar to RRT than to commuter rail systems terminating in stub-end stations. Systems called "commuter" in Boston, Chicago, and San Francisco (Caltrain) are ac-tually between these two modes. They are diesel-powered but provide hourly services throughout the day, although usually hourly only.

As described in Chapter 4, many cities (Paris, Brus-sels, Oslo, Philadelphia, Manchester) have upgraded their commuter networks into regional rail by con-necting stub-end terminals across central cities, elec-trifying the lines, and integrating them with regular transit.

Similar to other neighboring modes, there is no sharp boundary between commuter and regional rail modes. Yet a typical commuter rail system, such as diesel-traction TriRail in Miami and Metrolink in Los

Angeles, is very different from typical regional rail lines, such as Hamburg S-Bahn, Paris RER, and Sydney CityRail. The former, commuter lines, operate several inbound trains in the morning and outbound in the afternoon; the latter, regional rail lines, operate with 5-20-minute headways throughout the day. SEPTA's Regional Rail System in Philadelphia, NJ Transit Rail-roads, Metro-North, and the Long Island Rail Road fall in between these two modes.

Both commuter and regional rail modes are strong candidates for expansion or introduction in many cities, particularly in North America, due to their extensive suburban developments and congested freeways.

12.3.6.4 Regional Rapid Transit. Several cities or urbanized regions in the United States, such as the San

12.3 HIGH-PERFORMANCE TRANSIT MODES 605

Photo 12.20 Electric regional rail—S-Bahn in Germany.

Francisco Bay Area, Washington, Philadelphia, and Atlanta, which decided in recent decades to build high-performance transit systems, designed rail systems with networks similar to regional rail: long lines into suburbs with long station spacings, high operating speed, and heavy reliance on bus feeders, park-and-ride, and kiss-and-ride. Unlike regional rail, however, they penetrate center city through tunnels and have a number of stations in the central area with extensive transfers to other transit modes, including LRT and buses. Another feature of these systems is that their operation is the same as that of RRT: enclosed stations with high platforms allow short headways and high capacity. These systems thus represent regional rapid transit, or an actual bridge between regional rail and RRT modes. In a way, these systems have metro-type

in-city networks extending into regional rail suburban lines.

12.3.7 Trends in Regional Rail Transit Development

With rapid spatial growth of cities and urbanized areas, regional transit is growing in importance and has been the scene of intensive developments. Major develop-ments in this group of transit modes are listed and briefly described here.

1. Activation of abandoned railway lines or shared use of freight railway lines for transit services. These actions require investments as well as or-ganizational arrangements for shared use of

Photo 12.21 High-speed regional rapid transit with high comfort level effectively competes with auto travel—San Francisco BART.

12.3 HIGH-PERFORMANCE TRANSIT MODES 607

tracks. In some cases, such as in Los Angeles, the transit agency has purchased hundreds of kil-ometers of lines from freight railroads.

2. Upgrading of commuter rail into regional rail lines. This involves introduction of regular head-ways, usually of 20-30 minutes, which greatly facilitate transfers and integration of lines of the same mode or among modes.

3. Integration of regional rail with city transit. This includes such activities as joint stations, coordi-nation of schedules, joint fares, integrated infor-mation, and marketing.

4. Building connecting lines between stub-end rail-way stations at the fringes of city centers. With excellent results from these connections built in Munich, Oslo, Paris, Philadelphia, Ziirich, and

other cities, building such center city connec-tions is a logical step in upgrading regional rail networks in Boston, New York, and many other world cities.

5. Upgrading of diesel to electric traction. This fa-cilitates faster operations, ability to operate in tunnels, and use of shorter trains without loco-motives.

6. Physical integration of regional rail with RRT: joint use of tracks by different operators, used in several Japanese cities.

7. Tram-train concept: Integration of LRT with re-gional rail and even with intercity rail services. Examples are Karlsruhe and Saarbriicken in Ger-many, Manchester in Great Britain, and the River Line in southern New Jersey.

Photo 12.22 Light regional rail with diesel propulsion—River Line, southern New Jersey (courtesy of James Aslaksen).

Photo 12.23 (a) Dual system light rail/regional rail on center city alignment—Saarbrucken; (b) dual system light rail/regional rail on intercity railway line—Saarbrucken.

609 EXERCISES

8. Development of self-powered diesel passenger cars capable of running on railway as well as on transit lines. This rolling stock enables low-cost operation on regional railway lines with low to medium passenger demand, expanding the fea-

sible domain of regional rail services at its lower end.

With the increasing need for high-performance re-gional transit services, further experience and innova-tions in this field should be expected in the future.

EXERCISES

What is the most significant single physical improvement of transit needed to increase its 12.1. performance and competitiveness with auto, and why?

12.2. Compare rights-of-way B and C: 12.3.

a. What is required to upgrade a transit line from operating on ROW C to ROW B in

12.4.

terms of physical changes, investments, and possible external impacts? b. List and explain the potential benefits that can be obtained by such upgrading. Include

changes in LOS, operating costs, impacts on line image and ridership, and possible change in modal split.

Define the differences between transit lines with ROW B and those with ROW A. Under what conditions are the advantages of ROW A particularly important? What are the limitations on providing ROW A? Exclusive ROW for transit:

12.5. 12.6.

a. What are its economic, operating, and system characteristics? b. How does it influence transit ridership? c. How does it influence the role of transit in urban transportation? d. Where should it be used? Select two different modes, such as RB and LRT, BRT and AGT, or LRT and RRT, in a city you know well and descriptively define their PCPs. Which elements comprise their Performance in the selected case? Why should these two systems or modes be compared by their PCPs rather than by their costs only?

12.7.

Compared to steered highway vehicles, what characteristics do guided modes have? Which conditions favor the introduction of guided systems? List and discuss the advantages and disadvantages of electric as compared to ICE (diesel) traction. Then answer the following questions:

12.8. 12.9.

• Under what conditions is electrification not used? • Which conditions or type of alignment require electric traction? • Why do high-performance modes always use electric traction? Buses are often described as a "flexible mode." What are the advantages and disadvan-tages of that modal characteristic? How does upgrading an RB line into BRT affect its "flexibility"? What is the rationale for converting two lanes on a street from general use to bus lanes? What are the advantages of such a conversion for bus users? Under what conditions are bus lanes justified, effective, and permanent?