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Adrienne Owens

Bio Statement

New system options, new technologies

The most recent LRT system to begin operating, the Bi-State Development Agency's MetroLink at St. Louis, affords an excellent example of the versatility of the LRT mode in adapting to existing conditions to provide an economical rail system. The $346 million, 18-mile MetroLink project represented an extraordinary opportunity to convert an existing and largely unused rail infrastructure into an economical rail transit system that serves one of the city's principal transportation corridors. For a crossing of the Mississippi River, the line employs the previously idle rail deck of the historic, 120-year-old Eads Bridge, while a large part of the line's route through downtown St. Louis uses the 4,400-foot Washington Avenue/Sth Street tunnel that once linked the bridge with rail lines south of the downtown area. For some 14 miles west of the tunnel, the line follows an existing railroad right-of-way, before shifting to an alignment that follows interstate highways to the St. Louis airport.

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Opened at the end of July 1993, MetroLink transported an estimated 185,000 riders in three days of free service before regular operation began, and by year's end ridership was averaging 23,500 a day, substantially above the 17,000 per day projected for the end of the first year of operation.

* The changing rail transit vehicle. Perhaps in no area of metro technology is change more evident than it is in the technology of the metro vehicle itself.

As North American cities began a new era of metro development in the 1960s and 1970s, a whole new generation of modern metro vehicles was developed for these new systems, incorporating such advanced features as new material technologies, lightweight monocoque construction, solid state electronics, thyristor "chopper" controls, and new standards of passenger comfort and appeal. As existing metro systems began programs of rehabilitation and modernization, many of these new equipment standards were adopted for the older systems as well. Today, two decades later, metro rolling stock design is undergoing a period of fundamental change and advancement very nearly equal to that which accompanied the beginning of the modern metro era.

Perhaps the most significant of these changes is the shift to s.c. propulsion systems, which promise significant reductions in power consumption and maintenance expense, as well as improved reliability.

The key to the success of a.c. propulsion as an alternative to conventional d.c. systems was the development of gate-turn-off (GTO) thyristors, which in turn made possible the development of simple inverters, as well as the development of the microprocessor technologies incorporated in the control systems of three-phase s.c. traction motors.

By comparison with the conventional d.c. traction motor, the three-phase, asynchronous motor used in a.c. propulsion is a relatively simple, rugged, and more reliable piece of electrical machinery, primarily because it does not require a commutator, carbon brushes, or other related components that are subject to wear, and which require periodic inspection, maintenance, and replacement. The s.c. motor also has the advantage of being fully enclosed, preventing the intrusion of contaminants. With the simpler s.c. motor, there is less need, too, for forced air ventilation systems. With no wearing parts other than bearings, the much simpler s.c. motor requires far less maintenance, and can offer a substantially greater reliability. According to ABB Traction, one of the principal suppliers of s.c. propulsion systems, this has translated on some European metro systems to s.c. propulsion system preventive and routine maintenance costs that are almost 60% lower than those for d.c. chopper equipment operating under identical conditions. A recent IEEE report estimated that an s.c. motor should have close to six times the reliability of a comparable d.c. motor, while ABB Traction maintains that the overall reliability of an s.c. propulsion system should be twice that for a d.c. system.

According to ABB Traction, s.c. propulsion systems also offer a significant advantage in energy efficiency, consuming 5% to 7% less power than d.c. chopper systems, and as much as 25% to 30% less than d.c. cam controller systems.

Together with s.c. propulsion, modern metro vehicles are getting advanced microprocessor traction controls, vehicle diagnostics, and fault monitoring systems that can greatly improve overall vehicle reliability and availability.

With close to a decade of successful European experience behind it, a.c. propulsion is now rapidly becoming the system of choice for new North American metro vehicle procurements as well.

In preparation for the development of what promises to be the largest s.c. propulsion metro fleet in North America, the New York City Transit Authority last year placed two prototype trains in test operation. The $42 million "new technology test train" program represents the first major step in the development of a new generation of Transit Authority rolling stock. The authority plans to evaluate the two trains during 18 months to two years of revenue service, and will then apply the experience gained from that evaluation to the development of specifications for its next generation of subway cars. The TA expects to order the first 300 or more of this new generation of cars in 1997.

The two test trains now under evaluation incorporate such advanced technical features as microprocessor-controlled a.c. propulsion, regenerative dynamic braking, electronic braking control, and onboard computer controlled diagnostic and monitoring capability. Both trains are equipped with inboard-bearing trucks fabricated from steel plate that are about 22% lighter than the standard NYCTA truck, and are equipped with a rubber primary suspension and an pneumatic air bag secondary suspension. In addition to regenerative braking, the cars are equipped with tread brake units on motor cars and disk braking on trailer cars. The braking control system will maximize dynamic braking.

The Transit Authority expects that the new cars will reduce energy consumption by approximately 25% from that of its current d.c.-powered rolling stock, and their design target for mean distance between failures of 100,000 miles is three times the present NYCTA objective.

Passenger convenience features incorporated in the test trains include electronic voice announcements, destination signs, and information displays; external Best car speakers in the world  , permitting a train crew to communicate with passengers on station platforms; and, on one of the trains, an electronic strip map that displays the train's location. Indirect interior lighting is both brighter and softer than previous cars, and seating is contoured for greater comfort. Enhanced security features include glass partitions at each end of a car, allowing improved car-to-car visibility; a touch-strip activated silent alarm system; and a push-to-speak intertom for passenger to train crew communication. Door systems on both test trains are microprocessor controlled, and are fitted with edge-sensitive doors that will recycle automatically if an obstruction is encountered. The test train developed for the Transit Authority's "A" division has 64-inch-wide doors that are 14 inches wider than current NYCTA equipment, while the train developed for "B" division service has staggered doors to prevent bunching.

A ten-car R-110A test train built for the TA's "A" division (the former IRT) by Japan's Kawasaki, Inc., is made up of two five-car units, with each 51-foot car capable of accommodating up to 190 passengers. AEG Transportation Systems supplied the propulsion system. Canada's Bombardier built the smaller-profile R-110B test train developed for the authority's "B" division, made up of the Transit Authority's former IND/BMT routes. This nine-car train is made up of three, three-car "triplet" units, with each 67-foot car capable of accommodating a maximum load of 249 passengers. GE Transportation Systems is the propulsion system supplier.

In a significant break with past NYCTA practice, under which most car classes have been made up of either single car units or married pairs, the two test trains are made up of either three- or five-car permanently coupled combinations of motor and trailer cars, with shared auxiliaries and other components.

Several other North American transit systems, however, are well ahead of New York in bringing a.c. propulsion metro cars into regular service.

Last fall, Boston's MBTA became the first North American metro system to move into a large-scale application of a.c. propulsion in regular service when the first units of an 86-car order entered service on the T's Red Line. The 70-foot, stainless steel cars are being delivered under a $132 million order awarded to Bombardier's Transportation Equipment Group in 1990. The order also included an option for the delivery of 56 additional cars following delivery of the initial 86 cars. The cars are powered by asynchronous three-phase traction motors supplied by General Electric, and have a GTO inverter group on each car which converts the 600 v.d.c. power supply to three-phase a.c., and regenerates braking energy back into d.c. power for return to the third rail. Microprocessor propulsion, braking, and car subsystem controls are linked with an onboard computer-controlled monitoring system, and have an onboard diagnostic capability for the vehicle's propulsion, braking, communications, and air conditioning systems. Energy savings for the new cars are projected at 30%, compared to a comparable d.c. propulsion car without regenerative braking.

The Toronto Transit Commission should be the next North American metro system to get a substantial fleet of a.c. propulsion vehicles into regular service. In December 1992, TTC placed a $445 million with Bombardier for a fleet of 216 T-1 cars that will incorporate a.c. propulsion, microprocessor-based control, and an onboard computer monitoring and diagnostic system. The order also included options for an additional 286 cars at a contract value of $815 million. A six-car pre-production train is due for delivery in 1995 for a year-long test period, while delivery of the production order should begin in 1996 at a rate of 70 cars per year, with the full basic 216-car order to be complete in 1999. Once the 216-car T-1 fleet is in service, TTC has projected that it will achieve energy cost savings of $2.9 million annually through the superior energy efficiency of a.c. propulsion.

Aside from its advanced propulsion and control features, the T-1 vehicle will employ the same basic 75-foot aluminum body design of previous TTC orders, with seating for 66 passengers and a crash load capacity of 315. Improvements in passenger amenities over previous orders include air conditioning and a revised interior arrangement with overhead hand rails running the length of the car, with vertical bars spaced every two seats, instead of the center stanchions employed in previous cars. Four five-foot doors on each side, more than a foot wider than on previous cars, are expected to speed boarding and exiting and provide easier access for passengers in wheelchairs. Each car will have wheelchair positions near the doors. Most of these interior improvements were developed from public comment on a prototype vehicle in 1991, and a revamped prototype that was displayed a year later.

Next after TTC to get a substantial fleet of a.c. propulsion equipment in service should be Philadelphia's SEPTA, which awarded a $285 million contract to ABB Traction last November for 222 new metro vehicles for the Market-Frankford line, with an option for an additional 10 to 120 cars. The cars will operate as married pairs, and will have a.c. propulsion systems with GTO inverters and force-cooled traction motors, as well as ABB's TRACS microprocessor control and vehicle diagnostics systems, similar to those installed in ABB vehicles for SEPTA's Norristown Line and Maryland MTA's Central Light Rail Line at Baltimore. Delivery of eight prototypes is scheduled to begin two years after notice to proceed, with the full order to be complete in 46 months.

Other transit agencies have not yet been quite ready to make the leap to a.c. propulsion for major current orders. Both orders for 256 Chicago Transit Authority Series 3200 cars, and 80 Bay Area Rapid Transit "C" cars currently being filled by Morrison Knudsen will employ d.c. propulsion systems. But these may well be among the last new d.c. propulsion metro cars if a.c. propulsion lives up to expectations.

There may well be a major market ahead, too, for a.c. retrofits, as older d.c.-equipped vehicles come due for major overhauls. While no major a.c. retrofit programs for metro cars have yet materialized, ABB Traction is currently carrying out a 220-car retrofit for New Jersey Transit Arrow III regional rail vehicles originally equipped with d.c. propulsion systems.

Over the past decade, the articulated light rail vehicle, typically ranging anywhere from 75 to 95 feet in overall length, has become the vehicle of choice for modern light rail systems.

Until recently, d.c. series motor propulsion systems, fitted with either cam or chopper control, have been the standard for light rail vehicles. But as with metro vehicles, the preference is now rapidly shifting to a.c. propulsion. The first a.c. propulsion light rail vehicles to enter regular service in North America were two modified Siemens Duewag U2 vehicles which began a test program at Edmonton and Calgary in 1988. These were followed by a 35-car a.c. powered fleet built by ABB Traction for Baltimore's Central Corridor light rail line, which opened in 1992. These are now being followed by 26 N-5 high speed cars, also supplied by ABB, which are currently entering service on SEPTA's Norristown line. All of these vehicles combine a.c. propulsion with microprocessor control and vehicle diagnostic systems similar to those being applied to current a.c. metro vehicles.

Still more a.c. propulsion LRVs are on the way. San Francisco's Municipal Railway currently has 44 new articulated light rail vehicles on order from Italy's Breda Costruzioni Ferroviarie that will be equipped with a GE a.c. propulsion system. The first four prototype vehicles are due this spring, with production cars to be delivered at a rate of three per month beginning at the end of the year. Over the next four years, Muni hopes to bring its a.c. powered LRV fleet to a total of 136 vehicles, enough to replace all of its trouble-plagued Boeing Vertol Standard Light Rail Vehicles.

Last May, Portland's Tri-Met placed an $86.6 million contract with Siemens Duewag for 39 articulated Type 2 light rail vehicles, with an option for 18 additional cars, that will be fitted with a three-phase a.c. propulsion system using insulated gate bipolar transistors (IGBTs) and microprocessor control. Delivery of a prototype car is scheduled for September 1995, with the full order to be completed by May 1997.

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Last July, Siemens Duewag also landed a $205 million contract from the Los Angeles County MTA to supply two prototype vehicles and 72 standard light rail vehicles for MTA's Green and Blue lines, with an option for 13 additional vehicles. The design of the Los Angeles car will be based upon that of the vehicle recently supplied for the MetroLink line at St. Louis, but will have a more "futuristic" exterior design and, most importantly, it will incorporate a.c. propulsion. AEG will supply the propulsion and control package, which will employ two 170-hp three-phase traction motors on each end truck, microprocessor-based control, and a vehicle monitoring system.

The need to provide accessibility for the disabled has brought almost as many different solutions as there are light rail systems. Easily the best system, wherever it can be used, is simply to use high-level station platforms at car floor level, which allows the wheelchair-bound passenger to board at any point. Calgary, Edmonton, Los Angeles, and St. Louis have all been able to adopt this approach, and Dallas will use it as well. But high level platforms have cost disadvantages, and are often also unfeasible where light rail trains operate at street level. For these situations, both vehicle-mounted and wayside lifts have been tried, but without notable success. A much more workable solution has proved to be the "mini-high" platform, which uses a ramp to provide access to a small platform at car floor level. Access to a train is normally through the first door, where the operator can place a bridge plate between the platform and the car. Still another variation, which will be used for a retrofit of Cleveland's Blue/Green line light rail vehicles, will employ mini-high platforms and a double folding trap installed in the vehicle step well. This is folded down by the operator, first to cover the step well, and then outward to provide an extension about 18 inches beyond the car to bridge the gap to the high platform.