The class 2900 was the last class of 4-8-4 passenger locomotives ordered by the Santa Fe. They numbered 30 and like all previous ones, they were built by Baldwin. Basically the same design as the class 3765, they fell under wartime restrictions. This meant that they could not be built with strong lightweight alloys, what increased their weight by around five tons. In the result, these were the heaviest passenger steam locomotives ever built.

The firebox had a combustion chamber that was 84 inches or 2.14 meters long and contained thermic syphons. Other features were a Worthington feed water heater and Timken roller bearings on all axles. During the war, they were mandated to haul freight and clocked nearly 10,000 miles per month on average. After the war ended, they hauled passenger trains until the late fifties. In 1959, 24 were scrapped while six were preserved. 2926 was started to be restored in Albuquerque, New Mexico in 1999. It made the first run under its own power in 2021.