Bart did buy 30 cars for the Airport Extension. They were part of the C1 car order. BART has always had surplus cars. What limits BART's capacity is not cars, it is the transbay tube, or more specifically, the Embarcadero station. Trains can not move quickly through the tube because there is always a train stopped right at the west end of the tube. You can feel it when you ride in the rush hour if you know what you are feeling for. Bart has cars in the active fleet and cars out of service. Maintenance does cost money and they try to avoid maintaining cars that are not needed every morning at 4 AM. Reducing maintenance time reduces the size of the active fleet, which reduces maintenance cost. As far as purchasing new cars, car builders will be happy to build Bart one car. But the cost of Bart cars, the cost of any transit car, goes down as the quantity goes up. And track gauge is not the only thing that makes a Bart car unique. In fact it is a minor issue. Bart cars are low, light, wide, and have to be crash compatible. Just like most other transit cars, they have many car features that are unique to the Bart system. Like it or not, Bart is what we have. It is up and running and will continued to expand. The problem with Bay Area transit is the lack of a single regonal rail transit operator with regular funding.