The new 9.2 Detraining:
• Any hex that is not an Enemy Controlled City, Adjacent to one, or in an EZOC, and can trace an
Overland Supply Path of three hexes maximum (i.e., no more than two intervening hexes) to a
friendly Supplied City or friendly map edge.
Just to clarify the text 'Adjacent to one'; this includes an empty enemy controlled city?
Even if the target hex is occupied by a friendly unit?
YES! The rail nets were mostly going in to these cities. Not controlling those places would mean that rail deployment would be very hard to do.