The Atchison, Topeka and Santa Fe railroad arrived in Las Vegas in 1879, a roundhouse was needed so that locomotives could be serviced and stored. The first roundhouse in this location opened in 1880 and accommodated at least seven engines. A year later, four additional stalls were added, and a 54 foot turntable was installed. Several additions followed, before the roundhouse burned in 1917.
The AT&SF replaced the burned roundhouse with a 34 stall roundhouse on a reinforced concrete structure, incorporating and then expanding the original turntable. Just four years later, in 1921, the roundhouse was made obsolete by the availability of more durable locomotive parts and the change to diesel rather than stem power. This allowed engines to run directly from La Junta, Colorado to Albuquerque, New Mexico without stopping for inspection and repairs in Las Vegas.
During peak times, there were 380 men employed around the clock in three shifts at the roundhouse.
From the location of the cache, you can see the roundhouse. Don't attempt to enter, as it is private property.
Congratulations to the First to Find, Outdrlvr201!