The rolling stock of the Bay Area Rapid Transit (BART) system consists of 782 self-propelled electric multiple units serving the main BART system, built in four separate orders, four permanent three-unit cable-car trainsets in a Cable Liner system connecting Oakland San Francisco Bay Airport, and eight Stadler GTW diesel multiple units on the eBART branch line.
Pre-pandemic, to run a typical peak morning commute, BART required 579 cars. Of those, 535 are scheduled to be in active service; most of the others are used to build up four spare trains (used to maintain on-time service). The remaining 90 cars are in for repair, maintenance, or some type of planned modification work. All trains on the separate automated guideway transit line are in regular use without spares. Alstom (originally Bombardier) is manufacturing a complete replacement of the mainline fleet. With the withdrawal and retirement of the older fleet, there will be 775 vehicles in total, with long-term goals of eventually increasing this to 1,200 cars.
The automated guideway transit line utilizes off-the-shelf cable car technology developed by Doppelmayr Cable Car: the Cable Liner. The eBART extension was constructed to more traditional specifications and uses Stadler GTW articulated diesel multiple units previously utilized in other systems.
The mainline track gauge is , significantly wider than the used on the national passenger and freight railroads and most rapid transit systems in North America. In the past it also used flat-edge rail, rather than typical rail that angles slightly inward. These factors have complicated maintenance of the system, as it requires custom wheelsets, brake systems, and track maintenance vehicles. Stations have a platform height of . A full consist, which will fill the system's platforms, is ten units, equaling . BART trains are unique among American rapid transit systems as they have proper gangway connections and passengers are permitted to walk between cars, but it is not an open gangway system.
The legacy fleet was removed from regular service on September 11, 2023, but BART kept some cars as a reserve fleet for occasional use. The final operation of the legacy cars was at a decommissioning ceremony on April 20, 2024.
Original (legacy) fleet A and B series
The A and B cars were built from 1968 to 1975 by Rohr Industries, an aerospace manufacturing company that had recently started mass-transit equipment manufacturing. The first of these cars were delivered in 1970. The A cars were designed as leading or trailing cars only, with an aerodynamic fiberglass operator's cab housing train control equipment and BART's two-way communication system, and extending longer than the B-cars. A and B cars can seat 60 passengers comfortably, and under crush load, carry over 200 passengers. B cars have no operator's cab and are used in the middle of trains to carry passengers only. However, since each car is self-propelled, the B cars do have hostler controls allowing manual control as single units at low speeds inside a yard.
As early as 1978, BART realized that it had ordered too many A cars, which were unable to operate in the middle of train, and too few B cars. Over time, about 113 A cars (about of the A car fleet) were converted into B cars by removing their fiberglass cabs and installing the inter-car connection equipment.
BART previously operated 56 A cars and 341 B cars, and following their retirement on April 20, 2024, regular service will be of new cars only. To be able to maintain the vehicles until they are taken out of service, the workshop regularly procures computers on the second-hand market that can still address the old systems. Since the first series were newly designed, they had very few standard components, making them difficult to maintain.
C series
Just as BART had realized in the mid-1970s that it had ordered too many A cars, it also learned that it took more time than desired to change the length of a train. BART had originally planned to bring trains into yards after the morning rush and remove B cars to shorten the trains for midday service, before returning them to yards again to add cars for the evening rush. Ultimately this procedure resulted in long downtimes and increased the number of operators needed.
BART's solution to both issues was a new design, the C car. A C car has an operator’s cab like an A car but can also be used as an intermediate car like a B car. When placed in the middle of a train consist, the operator's cab is closed off and a door in the nose opens, allowing passengers to pass through to the next car (always another C car). This allowed BART to make one long train that could quickly break into two trains outside of a yard. Crews could also do the reverse and make one long train from two shorter consists. To add the operator’s cab while maintaining the same length as a B car, the C cars could only seat 56 passengers (a loss of four seats).
The first order of C cars, referred to as the C1 cars, were built by Alstom between 1987 and 1989. The second order of C cars, called the C2 cars, were built by Morrison-Knudsen (with shells built by Linke-Hofmann-Busch) from 1994 to 1996. At the time of their construction, the C2 cars featured flip-up seats which could be folded to accommodate wheelchair users; these seats were later removed during refurbishment.
The C cars had a bright white segment as the final approximately of the car at their cab end.
Refurbishments
After about 25 years in service, the A and B car fleet was rebuilt, using lessons learned when building the C cars, and the advances in technology since then. Among the changes were a conversion from DC to AC propulsion (detailed below), rebuilt trucks and suspension, and a complete cleaning and repair to the exterior and interior of the cars. The work was done between 1998 and 2002 at first by Pittsburg, California-based ADtranz and later by Bombardier which acquired the company in 2001.
A cars, (fleet numbers 101–276) were either rebuilt while retaining their cab (and renamed A2 cars, fleet numbers 1164–1276), or rebuilt without a cab (converted into B2 cars, fleet numbers 1838–1913). B cars (fleet numbers 501–774, 801–837) were rebuilt into B2 cars (fleet numbers 1501–1774, 1801–1837).
Because one of the original design goals was for all BART riders to be seated, the older cars had fewer provisions such as grab bars for standing passengers. In the late 2000s BART began modifying some of the C2 cars to test features such as hand-straps and additional areas for luggage, wheelchairs and bicycles. These new features were later added to the A, B, and C1 cars.
Prior to 2012, all BART cars featured upholstered seats. It was reported in 2011 that several strains of molds and bacteria were found on fabric seats on BART trains, even after wiping with antiseptic. These included bacteria from fecal contamination. In April, BART announced it would spend $2 million in the next year to replace the dirty seats. The new seats would feature vinyl-covered upholstery which would be easier to clean. The transition to the new seats was completed in December 2014.
Originally all the cars had carpeted flooring. Due to similar concerns regarding cleanliness, the carpeting in all of the cars was removed. The A and B, and C2 cars featured vinyl flooring in either grey or blue coloring, while the C1 cars featured a spray-on composite flooring.
Traction motors Prior to rebuilding, the Direct Current (DC) traction motors used on the 439 Rohr BART cars were Model 1463B with chopper from Westinghouse, who also built the automatic train control system for BART. The Rohr cars were rebuilt with ADtranz model 1507C 3-phase alternating current (AC) traction motors with insulated-gate bipolar transistor (IGBT) inverters. The Westinghouse motors were retained on the Alstom C (C1) and Morrison-Knudsen C2 cars and the motors that were removed from the Rohr cars were kept as spares. Cars have a starting acceleration of and are capable of holding that acceleration up to . Residual acceleration at is . Braking rates range from up to (full service rate).
The HVAC systems on the Rohr BART cars before rehabilitation were built by Thermo King, when it was a subsidiary of Westinghouse. The current HVAC systems on the rebuilt Rohr-built Gen 1 cars were built by Westcode and possibly also ADtranz who had subcontracted the HVAC system to Westcode.
Noise
Many BART passengers have noted that the system is noisy, with a 2010 survey by the San Francisco Chronicle measuring up to 100 decibels (comparable to the noise level of a jackhammer) in the Transbay Tube between San Francisco and Oakland, and still more than 90 decibels in 23 other locations. According to BART, the noise in the tunnel used to be "compared to banshees, screech owls, or Doctor Who's TARDIS run amok".
However, then-chief BART spokesperson Linton Johnson stated that BART averages 70–80 dB, below the danger zone, and according to a 1997 study by the National Academy of Sciences, BART ranks as among the quietest transit systems in the nation. Critics have countered that this study analyzed straight, above-ground portions of different systems throughout the country at , which is not representative of actual operating conditions. Much of BART is under ground and curvy, even in the Transbay Tube, and has much higher peak operating speeds than many other systems in the country.
Train noise on curves is caused by the wheels slipping along the rails. This slippage also causes noise and surface damage called corrugation. The process by which the noise and corrugation occur is: Pairs of wheels are attached to one another with an axle such that they must have the same rotational speed, but on a curve the distances the outer and inner wheels travel are different. As a result, the wheels must slip along the rails. This slippage causes the wheel and track to wear and become uneven (corrugated). This corrugation causes more noise and corrugation, not only in the original location but elsewhere in the system. In 2015, after replacing and grinding down (smoothing) of rail in the tube, BART reported a reduction of noise there and positive feedback from riders. BART also announced that the new train cars expected to enter service in December 2016 (see below) will be quieter, thanks to "'micro-plug' doors [that] help seal out noise".
Decommissioning If Federal Transit Administration funds were used in the purchase of a vehicle and that vehicle is deemed to have a value over $5,000 at the time of sale, the FTA is entitled to a reimbursement proportional to its contribution to that vehicle when it was initially bought. This applies even if the car is donated free of charge.
The older cars began retirement in November 2019 when car 2528a C2 carwas the first released from BART ownership. The car had been removed from service in 2014, by which time it had run and was held in reserve for spare parts. Four additional C2 cars, three B2 cars, and two C1 cars (totalling ten cars) were also sent to the Schnitzer Steel facility in Oakland to be evaluated and recycled.