Rapid transit trains have 4–10 cars, the maximum length of 710 feet (216 m) being the longest of any metro system in the United States and extending slightly beyond the 700-foot (213 m) platforms.
https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit#Infrastructure
https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit#Car_types
https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit#Future_railcars
https://en.wikipedia.org/wiki/Silicon_Valley_BART_extension
