No. 2156 was manufactured by Baldwin in 1909 for the Northern Pacific Railroad. It is currently in restoration.
Northern Pacific Class Q-3 4-6-2
The 4-6-2 type, or "Pacific", was the predominant steam passenger locomotive during the first half of the 20th century. Between 1902 and 1930, about 6800 locomotives of the type were built for U.S. and Canadian service.