State-of-the-Art Car
| Company type | Prototype rail vehicle |
|---|---|
| Industry | Rail transport |
| Predecessor | R44 subway car (design elements) |
| Founded | 1972 |
| Founder | United States Department of Transportation's Urban Mass Transportation Administration |
| Headquarters | Kennebunkport , United States |
Area served | United States (various cities) |
| Products | Heavy rail transit prototype vehicles |
| Parent | St. Louis Car Company (manufacturer) |
The State-of-the-Art Car (SOAC) was a heavy rail transit prototype developed during the 1970s under the United States Department of Transportation's Urban Mass Transportation Administration. Created to demonstrate cutting-edge transit innovations and support both existing and planned lines, a single married pair was manufactured by the St. Louis Car Company in 1972. These vehicles operated intermittently across six rapid transit networks in five American cities from May 1974 through January 1977. Since 1989, both units have been exhibited at the Seashore Trolley Museum located in Kennebunkport, Maine.
Design and development
In the early 1970s, UMTA launched the Urban Rapid Rail Vehicle and Systems Program aiming to develop a new rapid transit vehicle focused on enhancing passenger comfort, safety, dependability, and noise reduction to boost ridership. Boeing Vertol assumed project management for the SOAC initiative starting in 1971.
The contract to build a two-car demonstrator set was awarded to the St. Louis Car Company, prevailing over competitors such as Budd, Pullman-Standard, Rohr Industries, and Vought. The design incorporated significant elements from the R44 subway car—recently produced for New York City Subway—and integrated features inspired by Bay Area Rapid Transit rolling stock. Completed in 1972 alongside the R44 production, these units were among the final products by St. Louis Car Company. Each SOAC unit cost approximately $350,000 compared to $300,000 for each R44 car.
Engineered to accommodate the loading gauges of rapid transit systems in Boston, Chicago, Cleveland, New York City, and Philadelphia, the SOAC was restricted to certain lines—such as New York City's B Division and Chicago's Skokie Swift—due to gauge limitations elsewhere. Its dimensions closely resembled those of the R44: roughly 74 ft 8½ in in length and 9 ft 9 in in width, with adjustable floor heights ranging from 11 ft 8½ in to 12 ft 1½ in to align with platform elevations.
Two seating configurations were offered: a "Lo-Density" version seating 220 passengers and a "Hi-Density" variant accommodating up to 300 passengers. The "Hi-Density" model combined transverse and longitudinal seating totaling 72 seats; the "Lo-Density" car featured 62 seats arranged into three sections with various seat types and tables. Both cars were classified as "A" cars with operator cabs at one end. Power collection primarily utilized third rail systems but switched to overhead lines when operating in Chicago and Cleveland.
Testing
Initial testing of the SOAC took place at the High Speed Ground Test Center in Pueblo, Colorado. On August 11, 1973, a collision caused by an improperly set switch resulted in the operator's fatality during testing, raising safety concerns regarding the vehicle’s design.
Following these early evaluations, the SOAC toured six rapid transit networks across five U.S. cities for further trials and public demonstrations. Two systems—BART and PATH—were excluded due to incompatible track or loading gauges.
Revenue operations commenced on the New York City Subway on May 17, 1974, with service on the A, D, E, and N lines until July 19. Subsequently, it operated on Boston's MBTA Red Line for one month beginning August 19, 1974. Later that year, it ran revenue service on Cleveland's CTS Airport Line for fifteen days.
In January 1975, the SOAC was deployed on Chicago Transit Authority's Skokie Swift for thirteen days; platform adjustments were necessary due to its larger dimensions. It then operated on Philadelphia's SEPTA Broad Street Line from March 6 to April 2, 1975. Throughout these trials spanning over approximately 104 days of operation, the SOAC transported about 312,000 passengers.
The demonstrator was then transferred to the PATCO Speedline, where non-revenue testing began on May 1, 1975. After necessary modifications and insurance approvals, nine months of revenue service started on August 12, 1976; however, operations ended on January 24, 1977 after only 23 revenue service days.
Passengers praised the SOAC for its quiet ride and air conditioning comfort while operators valued its ease of control. Nonetheless, transit agencies expressed mixed opinions about its overall benefits. In light of this experience alongside mixed results from the US Standard Light Rail Vehicle program, UMTA redirected efforts away from complete vehicle designs toward subsystem research. Several SOAC innovations—including acoustic engineering techniques, air-ride suspension systems, chopper propulsion controls, and traction motor ventilation—were later integrated into rolling stock by various agencies.
After completion of testing phases, both SOAC cars were stored at Boeing Vertol until May 1979; one unit was sent to Budd Company while the other returned to Pueblo for subsystem evaluation. In 1989, the two-car demonstrator was acquired by the Seashore Trolley Museum in Kennebunkport, Maine, where it remains preserved as a static exhibit.