Atchison, Topeka & Santa Fe 3751 is a class 3751 4-8-4 "Northern" type steam locomotive built in 1927 by the Baldwin Locomotive Works in Eddystone (Philadelphia), Pennsylvania for the Atchison, Topeka & Santa Fe Railway (ATSF). Built as the first 'Northern' type steam locomotive for the Santa Fe, No. 3751 served in passenger duties until being retired in 1957.

The locomotive was then placed on display in San Bernardino until it was restored to operating condition in 1991. It is currently located in the Central City East neighborhood of Los Angeles and is listed on the National Register of Historic Places. It holds the distinction of being the oldest surviving 4-8-4 type steam locomotive in the world.