Constant starting and stopping would be a performance and efficiency issue. A better way would be to have local trains that ran on parallel tracks and sync'd s

Constant starting and stopping would be a performance and efficiency issue. A better way would be to have local trains that ran on parallel tracks and sync'd speed with the main train and passengers and cargo would be xfered to the local train - alternately, traffic could be segregated into seperate cars by destination and then cars would be spliced back and forth between the local and main train.