The Atchison, Topeka and Santa Fe Railway's 3460 class comprised six 4-6-4 "Super Hudson" type steam locomotives built in 1937 by the Baldwin Locomotive Works for service between La Junta, Colorado and Chicago, Illinois, a fairly flat division of the railroad suited for the 4-6-4 type.

They were substantially larger than the road's earlier 3450 class locomotives, and all were built oil-fired, although in a manner that would allow for easy conversion to coal firing.

In December 1937, locomotive #3461 set a world record for the longest single run by a steam locomotive by completing the 2,227 miles (3,584 km) from Los Angeles, California to Chicago without maintenance other than five refuelling stops en route, hauling Train #8, the Fast Mail Express.

It was the Santa Fe's only streamlined steam locomotive, featuring extensively in railroad publicity.

It was initially planned to be restored to operating condition by the Coalition for Sustainable Rail (CSR), but after several years of delay and negotiations, the group was renamed to the Kaw Valley Rail Heritage Conservancy (KVRHC).