INTRO: Suppliers are due to be chosen this month for a pilot installation of transmission-based train control on NYCT’s F Culver line. William D Middleton assesses the proposals, which envisage that a lead supplier develops compatible equipment permitting competitive procurement in the future
INTEREST in transmission-based or communications-based train control (TBTC) is growing among North American rail transit operators. Much attention is now focused on New York City Transit, which is moving towards a pilot installation decision that is expected to establish TBTC standards governing signalling modernisation on North America’s largest rail transit network. And simply because NYCT represents such a large share of the potential North American signalling market, the standards adopted for New York are likely to govern what happens elsewhere in North America.
NYCT began detailed consideration of TBTC with a year-long study completed by Parsons De Leuw in 1993. This formed the basis for a planned system-wide changeover to the new technology that could take 30 to 40 years. NYTC at present uses very basic fixed-block signalling with single-rail track circuits and trip-stop protection, but without any form of overspeed protection. A moving block TBTC system was seen as one that could enhance safety, capacity and performance, and achieve a high degree of fault tolerance while reducing life cycle and maintenance costs.
Support for NYCT’s pilot TBTC installation is being provided by an Advanced Technology Signals Group (ATSG) consortium headed by Parsons Transportation Group/De Leuw Cather & Co of New York, and including ARINC and Booz, Allen & Hamilton, together with five sub-consultants. The programme has now reached the proposal review stage, and selection of three signal suppliers for a Phase I demonstration test is due this month.
Developing TBTC for New York is a daunting task. The subway carries 3·1 million people a day and includes 25 interconnected lines made up of 1162 track-km with 469 stations and 213 interlockings. Equipment includes more than 11000 track circuits and wayside signals, and over 9500 automatic train stop devices. More than 6000 cars are in use, with trains running 24 hours a day. Peak services have headways as close as 90sec.
For its pilot project, the agency has developed a performance and functional specification for a state-of-the-art communications-based train control package using two-way digital radio frequency communications between intelligent trains, with vehicle-borne equipment, and a network of distributed zone controllers. Principal characteristics will include high resolution track location determination, determination of movement authority limit information for each train, determination and enforcement of speed/distance profiles, and communication of data and commands between vehicles and wayside zone controllers, and between wayside controllers and interlockings. Central supervisory computers will provide train scheduling, and general operating and control information to provide optimal throughput, control and flexibility.
Procurement policy
A growing number of proprietary TBTC systems able to provide most of these characteristics is already on the market. While choosing one of these would minimise development costs, NYCT is concerned about the long-term cost liabilities associated with a single supplier.
Consequently, a key goal is to develop a non-proprietary system that will permit vehicle and wayside equipment to be supplied by more than one manufacturer. To do this, the procurement requires the development of interoperability interface specifications by a ’lead’ supplier that will permit future competitive procurement of wayside and vehicle-borne systems as additional segments are resignalled and new car contracts are awarded.
Under the agency’s phased implementation strategy, resignalling will proceed in parallel with new car procurement to minimise the number of older cars that will need retrofitting with TBTC. Each batch of new cars will have on-board TBTC equipment, while wayside installations will be made on a line-by-line basis.
’The real challenge in New York will be car to wayside interoperability’, says ATSG project manager Dr Alan F Rumsey. ’Interchangeability is not the objective’, he comments, ’but vehicle packages from one supplier must be able to work with wayside equipment by another supplier.’
An important exception will be wayside transponders, which will have to be standard for the entire network, says Rumsey. Much work has already been done, he adds, on standardising this equipment.
A widely debated topic has concerned the relative merits of placing intelligence functions on the vehicle rather than at the wayside. While the New York specification does not explicitly specify either alternative, it does require a highly fault tolerant system. Anticipating that there will be occasional momentary loss of communication between vehicle and wayside, for example, NYCT wants the system to be able to continue operating to the greatest possible extent.
’This pushes you towards putting most of the intelligence on the vehicle’, says Rumsey. ’With an intelligent vehicle you can carry on to the limits of authority in case of an interruption.’
While many operators do not consider broken rail detection to be a major requirement for TBTC, NYCT will require this capability at least to the single-rail level of its present track circuit signalling.
Test programme
The current pilot project procurement began with a request for proposals in October 1997. Technical proposals were received in February from Adtranz, Alcatel, GEC Alsthom Transport/General Railway Signal, Harmon Industries, Safetran, and Union Switch & Signal/Matra Transport International, followed by management and price proposals over the next two months.
The pilot project will have three major phases. This month NYCT will select three suppliers who will receive $1·1m each for a Phase I demonstration on a 3·2 km double track section of the F Culver line between Manhattan and Brooklyn. Systems supplied by each supplier will be tested in parallel, each using two R42 married pair car sets provided by NYTC. Each supplier must be able to demonstrate the ability to comply with the specification’s minimum requirements. Contracts are expected to be awarded to the three successful firms by September, with the six-month demonstration expected to begin early in 1999.
Based upon its evaluation, the agency expects to select a lead supplier and award a Phase II contract by late 1999 for resignalling its L Canarsie line with what will represent a NYCT ’standard’ TBTC system. This 17·2 route-km, double track line between Eighth Avenue in Manhattan and Rockaway Parkway in Brooklyn was picked because it is operated independently of other NYCT lines. The route combines tunnel, underwater tube, elevated, and at-grade sections and has 24 stations and seven interlockings. Vehicle-borne TBTC equipment will be supplied for 100 new R143 cars planned for the Canarsie line, and for retrofit on 60 existing R42 cars. Vehicle-borne equipment for the new cars will have full ATO capability, while the retrofitted cars will only have ATP capability.
For Phase III of the pilot project the lead supplier will provide detailed interoperability interface specifications, and NYCT will select two ’follower’ suppliers for $3m contracts under which they will develop compatible vehicle-borne and wayside TBTC systems and demonstrate compatibility with the lead supplier’s equipment on the Culver line. These Phase III contracts should be awarded by late 1999, interoperability specifications should be available by October 2000, and both the Phase II and III work should be completed by early 2004. By then NYCT should have three qualified suppliers for both vehicle-borne and wayside equipment for its subsequent TBTC installations.
New York’s Long Island Rail Road is likely to follow NYCT’s lead in adopting TBTC. for signalling modernisation. With traffic densities approaching those on NYCT, LIRR is planning a long-term TBTC signal strategy that is likely to adopt standards identical to those of NYCT. The commuter railroad is participating with NYCT in the Canarsie line project, which has been modified so that suppliers can demonstrate the ability to support additional LIRR requirements, including vital grade crossing control, train positioning using GPS, and vital communication between zone controllers by radio. o
CAPTION: The vast scale of New York’s subway makes it attractive business to potential TBTC suppliers, but will pose a formidable installation task
CAPTION: Fig 1. TBTC as envisaged for installation on the 1162 track-km NYCT network
New York définira les normes de transmission voie-machine pour l’Amérique du Nord
Des contrats seront signés en septembre avec trois fournisseurs de systèmes de contr
