The Time Travel Car can be used with or without the first expansion: Horses & Stagecoach.
The Time Travel Car is placed in front of the Locomotive.
The Time Travel Car is considered as adjacent to the roof and the inside of the Locomotive. So your Bandit can enter it thanks to a Move action or a Horse action if you play using the Horses and Stagecoach expansion.

Several Bandits can go in the Time Travel Car at the same time, but in order to trigger the action, your Bandit has to be alone in it at the end of a round (after applying the event, if the current round has one).< ...