The size of a commuter rail car is not standardized, and no typical or average dimensions are available. The dimensions vary with factors such as the make and model, location, year of manufacture, and whether it is a single- or double-level car.
To find the dimensions for a commuter or regional rail car, first find the manufacturer of the car, which has the specifications, including dimensions, of each model. Manufacturing information can likely be found online or by calling the company. For example, Bombardier is a manufacturer of commuter and regional trains and has detailed information including the dimensions available online for each model it produces.