Here is another approach. The passengers get on a helicopter which lands on a helipad on the train, and quickly get off. The disembarking passengers board the h

Here is another approach. The passengers get on a helicopter which lands on a helipad on the train, and quickly get off. The disembarking passengers board the helicopter on the train and fly back to the station. Benefits: Does not require complex and dangerous docking/undocking mechanism. Does not require perfect synchronization (unless there is a tunnel a mile from the station -- this can be avoided by planning stations more intelligently). Once the train is in operation I'd like to see the insurance rates on the infrastructure.