New York leads a revolution: communications-based train control for transit - CBTC

Railway Age, Sept, 1996 by William C. Vantuono

On the North American rail transit scene, developments in communications-based train control (CBTC) have been moving forward sort of like a running back in football: with a lot of energy and momentum, but with a fair number of obstacles to overcome before the end zone is breached.

Good progress continues to be made on the West Coast. At San Francisco, Bay Area Rapid Transit is expected to have a pilot overlay installation of AATC (Advanced Automatic Train Control) up-and-running on a section of main line track by mid-1997. Developed jointly by BART and Hughes Transportation Control Systems, AATC is an adaptation of military EPLRS (Enhanced Position Location Reporting System) technology (RA, August, p. 54).

Also at San Francisco, the MUNI light rail system plans to have an Alcatel-supplied SELTRAC inductive-loop-based system in full operation in the 6.3-mile Market Street tunnel by November 1997. It will allow 60 trains per hour through the tunnel on 40-second headways. MUNI says it will switch directly to full SELTRAC operation at that time; in the interim, new Breda-supplied LRV-2s, which were designed to accept SELTRAC onboard equipment, will be retrofitted with antennas that will allow them to operate on the existing cab signal system.

Overseas, London Underground's Jubilee Line is expected to be in service by 1998 with a CBTC system developed by Westinghouse Brake & Signal (the parent company of U.S.-based Safetran).

Last year around this time, it appeared that the Toronto Transit Commission would move rapidly forward with testing and implementation of as-yet-untried radio-based technologies. These were to be procured for two new subway lines. One, the Eglinton West line, was scuttled late in the year by the local government. The other, the Sheppard line, was canceled only recently. (Oddly enough, in a curious twist of Toronto politics, the tunnel for the Sheppard line-- but not the line itself-- was approved for construction.)

Two highly successful demonstrations of CBTC have been conducted at TTC-- General Railway Signal's ATLAS (Advanced Train Location & Supervision) system and GEC Alsthom Signarail's SACEM New Generation. Through the end of the year, Harmon will demonstrate the UltraBlock system, and ADtranz will demonstrate Flexiblok technology. (Prior to their merger into ADtranz, AEG and ABB were to conduct separate demonstrations, but AEG's Flexiblok was chosen by the new company.)

TTC, with construction of its hoped-for new lines floating somewhere in limbo, is now forced to move forward with CBTC technology on the existing Bloor-Danforth line. At best, CBTC will be installed on this line by 2005, around the same time as a rolling stock replacement program, but two years later than MTA New York City Transit's planned Canarsie Line CBTC start-up in 2003. That essentially puts NYCT--one of the world's largest rail transit systems--back in the lead among North American rapid transit properties for development of RF-based CBTC.

Despite the politically-induced roadblocks, TTC's demonstration program is showing that CBTC technology is here-and-now. "It is helping to build confidence in the technology," says De Leuw Cather's Dr. Alan F. Rumsey. "There's real hardware and real systems out there, so in the industry, we're rapidly moving from the development stage to the implementation stage. That's the challenge now--how to implement this technology, and how to deal with the institutional and operational issues."

There are three basic objectives at TTC:

--To demonstrate a reliable train-to-wayside communications system.

--To demonstrate the ability to locate a train independent of track circuits.

--To demonstrate basic train protection functionality.

"So far, these objectives have been met," says Rumsey. "Everything that has been done thus far in New York, Toronto, and San Francisco has given the industry confidence that reliable radio communications can be achieved in a subway environment, and that's the major area of technical risk,"

As for NYCT's CBTC program, it's moving full steam ahead, and is still the focus of intense interest world-wide. "What New York is doing is leading the world, however, we must bear in mind that New York is also going along with the world-wide trend toward CBTC," says Rumsey.

* New York presses on. Rumsey is project manager for the Advanced Technology Signals Group, prime consultant to NYCT's CBTC program. ATSG is a consortium of De Leuw Cather & Co. of New York, Inc., ARINC, Inc., and Booz, Allen & Hamilton, Inc. Abacus Technology Corp. (software validation and cost estimating); CANAC International (ATCS carry-over experience, training); Interactive Elements (operations and maintenance planning); Maitra Associates, P.C. (facilities design); TRW, Inc. (Communications); and Turner-Gold-France Engineering (electromagnetic interference issues) are sub-consultants. At present, says Rumsey, the NYCT project is in the preliminary engineering/system design phase.

"We're on track, on schedule," he says. "The last six months have been spent establishing operating requirements. We've used a top-down approach, with all the departments at NYCT that will be affected by CBTC (operations, maintenance, mechanical) involved in the process." By November, ATSG plans to complete general guidelines--an operating plan that ultimately will be issued to the industry for comments.