#1809 is one of fifty-seven Class 1800 balanced compounds delivered to the Santa Fe as coal burners between 1906 and 1907 (#1809 in 1906). Built by Burnham, Williams & Company, an early incarnation of the Baldwin Locomotive Works, they were amongst the biggest Prairie type (2-6-2) locomotives built for any US railroad. The high pressure cylinders were set 7° off the horizontal to clear the front axle and avoid having to use a forked main rod.
The 1800s have an engine wheelbase of 33' 9", a driver
wheelbase of 13' 8" and Walschaert valve gear. As built, they weighed 248,200 lbs, 174,700 lbs on the drivers. The high pressure cylinder was 17.5" x 28", the low pressure cylinder
29" x 28". The grate was 53.8 sq ft and the firebox 217 sq ft. With a total heating surface of 4,020 sq ft, they operated at a boiler pressure of 225 psi, delivering 34,846 lbs tractive effort.
In 1920, the Santa Fe installed 802 sq ft of superheating, increasing the total heating surface to 4,084 sq ft. Boiler pressure and tractive effort were unchanged, but weight increased to 260,132 lbs, 179,006 on the drivers.