Built in 1946, MNCR locos 413 and 412 were probably older than many of the exhibits in the adjacent Danbury Railway Museum. Amazingly 413 seems to have ended up at this museum!
Mount Washington Cog loco No 10 Kroflite leaves from the base station. No 10 seems to be much newer than the rest of the steam fleet, dating from 1972 according to Wikipedia.