Reply to "I found a reason for a turntable: maybe?"

you might want to take a look and Conway yard for NS.  Active turntable with engine facility and a whole let less room than Altoona.  For a whole different approach try the Western Maryland Scenic RR.  I can't remember the name at the end of the line but they still use  turntable there to spin the steamer before runs around the train for the return trip.