Longer Trains

 https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit 700 foot long with 10 car trains.

https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit_expansion#Proposed_extensions

https://upload.wikimedia.org/wikipedia/commons/thumb/2/29/BART_train_from_Farallones_Street_footbridge_%281%29%2C_July_2023.JPG 

https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit_rolling_stock#Fleet_of_the_Future_(D_and_E_series) Car length 70 ft (21 m)

https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit_rolling_stock#C_series

https://en.wikipedia.org/wiki/Bay_Area_Rapid_Transit_rolling_stock#Original_(legacy)_fleet