Someone mentioned the converse process where the loco is ahead, uncouples and speeds up, then the switch is thrown after it passes and before the cars do (known as the "flying switch"). This is dangerous (think about throwing the switch under the loco or after the first car has begun to pass it) and is probably illegal most everywhere. But I recently read that it was not only permitted but *normal* at Grand Central, where passenger trains (loaded!) were routinely cut into the terminal tracks in this way and stopped by the conductor or brakemen.
In Trainz (V 2.9 SP2) I find that the new "consist" (the cars) doesn't respond to stop or brake commands without a loco, though you can issue them. Issuing such commands to a driverless consist also seems to crash the game more often than not. But if you judge the speed at release just right, it can be quite effective without; the principal danger is that, as you admire your work (the cars coasting to a stop just short of the buffer) you forget about the loco as it crashes into something else or derails (g).
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