As Matt mentioned on the release stream, the 323 has not been added to the Training Center's timetable. You can only see the base game content when you spawn on foot. This is because if they add literally everything to this timetable they would run out of room on the map and run out of memory for the game. Yes, you can use the Scenario Planner to put a train there, but that doesn't provide the flexibility to just walk around and drive anything, which is the best part of the Training Center experience. My proposal is to add a small number of trains around the map that fit the general characteristics of each type of DLC and then enable substitution for these trains. This would allow you to spawn on foot and grab one of them randomly, or select one from the timetable menu like you can on a normal route. Every visit to the Training Center would then be different and potentially surprising. Add a long diesel that will appear as a US, Canadian or British freight train. Add a third-rail passenger service that could be an Electrostar, an M7, M3, M7A, M3A or one of the Island Line trains. Add an overhead line EMU that could appear as a 323, 313, or 314 (among others). Add an electric passenger train that could be a German train or an ACS-64 with Amfleets. Add a diesel passenger train that could be an MBTA train, a Caltrain or an old British train from ECW or NTP. I'm sure there's some other combination I'm forgetting. An alternative idea, but probably much more complicated to implement: Add a spawn control somewhere on the map where we can order up any train and have it emerge from a portal and park somewhere on the map. Then I can get in and drive it to the yard and go back and order another one.
