Built as a Vauclain compound, this Prairie type (2-6-2) locomotive was designed to operate over the AT&SF line between La Junta, CO, and Albuquerque, NM, with its steep grades between Trinidad and Raton. Burnham, Williams &
Co., an early incarnation of the Baldwin Locomotive Works, built forty of this Class 1000 locomotive (#1000-#1039) in 1901. They had an engine wheelbase of 32’ 2” and driver wheelbase of 13’ 8”.
As built, #1015 had two 17” x 28” high pressure cylinders and two 28” x 28” low pressure. By the time it was delivered, however, many US railroads were beginning to abandon compounds and were converting those they owned to single-expansion locomotives.
The first fourteen of the class were simpled between 1912 and 1918, the remainder, including #1015, between 1922 and 1924 with 28½” x 28” cylinders. Part of the modifications included replacing the original Stephenson valve gear with Walschaert and the 79” drivers with 69" in 1922-1923. The rebuild increased the engine weight from 209,220 lbs to 210,190 lbs, although the weight on the drivers dropped from 144,610 lbs to 141,690 lbs.