Santa Fe No. 5011
Atchison, Topeka & Santa Fe No. 5011 was the flagship of the 5011 class. This huge 2-10-4 "Texas" type locomotive is on display at the Museum of Transportation, St. Louis, MO, with the cab open to the public.
I photographed this incredible locomotive the day before the museum's 2002 farewell excursion of Frisco 1522.
When the Atchison, Topeka & Santa Fe Railroad purchased its last group of 2-10-2 locomotives it had the Baldwin Locomotive Works equip one of them (number 3829) with a four-wheel trailing truck to see what difference there would be between a 2-10-2 and a 2-10-4. This experimental locomotive, delivered in 1919, was the first ever of this wheel arrangement. The experiment ended without any conclusive results or any name given to this wheel arrangement, and number 3829 was kept in service as a 2-10-4 until it was retired in 1955.
Six years later, in 1925, the Lima Locomotive Works designed a new locomotive by adding a fifth set of drivers and increasing the cylinders of its "Berkshire" and created a 'true' 2-10-4. The first railroad to take delivery of this new 'super power' locomotive was the Texas & Pacific Railway in 1925. Because the AT&SF design was merely an experiment no name had been attached to the 2-10-4 wheel arrangement in 1919. After the delivery, in 1925, the 2-10-4 was given the name "Texas" for the Texas & Pacific. - SteamLocomotive.com