To get this you need to start up rapid transit and select services then pick a route that goes as far as possible. Start the service then press “y” to stand up exit either door and enter the coaches and sit down on any available seat.
Next just wait a box will pop up asking if you want to give up control of the service. Answer yes.
Then just wait for the train to start and the stay in position. Don’t stand up or use external cameras as the achievement will not track, it only works if your sat down.
Hope this is useful,