The N5 was the world's first all-steel caboose to go into large-scale production. Designed by the Pennsylvania Railroad and built at its massive complex in Altoona, PA, the N5 was produced from 1914 to 1942 with only minor changes to its basic design. On the PRR it was called a cabin car, while caboose originally was a slang expression. By law and union rules, every freight train was required to have a caboose as its last car until 1982. This caboose later served as an advertising prop for a Trane air-conditioning dealer in Ithaca, NY, before Ethan P. Jackman purchased it in 2006 and donated it to the Hudson Valley Rail Trail.