Sperry Rail Service detector car 137 takes a break from rail testing along Southern Pacific's Provo Subdivision mainline in the Salt Lake Valley. The car was built by St. Louis Car for the Soo Lin... (more)

The unmistakable pitch of a single chime air horn and a Caterpillar diesel engine announce the arrival of Sperry Rail Service car 144, testing for defects along Rio Grande's westward main track at... (more)

Sperry Rail Service car 137 performs rail defect testing along UP's remote Sunnyside Subdivision in eastern Utah. The car was built by St. Louis Car for the Soo Line in 1925. Sperry acquired it an... (more)