Atchison, Topeka and Santa Fe 3751 is a preserved class "3751" 4-8-4 "Heavy Mountain" type steam locomotive built in May 1927 by the Baldwin Locomotive Works in Eddystone (Philadelphia), Pennsylvania for the Atchison, Topeka & Santa Fe Railway (ATSF).

The locomotive was then placed on display in San Bernardino until it was restored to operating condition on August 13, 1991.

It is currently located in the Central City East neighborhood of Los Angeles and has been listed on the National Register of Historic Places since October 4, 2000.

It continued to be a very reliable working locomotive until August 23, 1953, when it pulled the last regularly scheduled steam-powered passenger train on the Santa Fe to run between Los Angeles and San Diego; this was its last run in revenue service before being put into stored at the Redondo Junction and retired from active service.

Four years later, it achieved its goal when 3751 was sold to it for one cent with the condition that the SBRHS must restore and operate the locomotive.

[6] The locomotive is currently owned by the San Bernardino Railroad Historical Society, the same organization that performed the initial 1986 restoration.

On the return trip to Los Angeles, the 3751 pulled another mixed train with eight covered hopper cars.

In August of 2002, 3751 operated an Amtrak excursion train from Los Angeles to Williams, Arizona to participate in the 2002 National Railway Historical Society (NRHS) Convention.

3751 also pulled some of GCR's Pullman passenger cars for a photo charter requested by Goodheart Productions.

The excursion made the locomotive the first steam locomotive to run on the Surf Line since the 1976 American Freedom Train, it was also the first steam powered passenger train to make the run between Los Angeles and San Diego since 3751 last traveled the line in 1953.

It has made annual runs to San Bernardino for the Railroad Days Festival in April or May since the initial trip.

[9][17] As part of the excursion, another special round-trip doubleheader to the Grand Canyon and back was run with 3751 and GCR 4960.

[17] The train also operated over the Arizona & California Railroad on the way to Williams and on the return trip to Los Angeles.

From April 30 - May 1, 2016, the 4-8-4 was on display again and left Fullerton two hours late due to rail traffic.

3751 participated in the Amtrak Track Safety community event at the Fullerton Transportation Center.