This HO scale model replica is based on the original Souther Pacific drawing, thanks to "Steam Age Equipment Co." and the "SP Historical & Technical Society", Showcase was able to view and copy the original drawings. The Water Pump House is a must for the steam era, however, they continued to stand long into the diesel era. Fits safely into early 1900's through1970's. This structure will occupy a space of about 2 1/4 x 2 1/4.