IMHO, your best bet for a "compressed " Altoona locomotive shops is to mimic the 12 st facility and NOT Juniata which is HUGE!
Clark Dunham who built the model at the Alrtoona RR's museum did a good effort and has some good effects..
http://dunhamstudios.com/publi...ers-memorial-museum/
I mean- it doesn't look that big from up here...