#421 was built as #1641 for the Union Pacific by Burnham, Williams & Co., an early incarnation of the Baldwin Locomotive Works, in 1901, one of fifty-eight Class 1640 Vauclain compound Consolidation type (2-8-0) locomotives (#1640-1699). In 1915, the class was renumbered Class 420 #420-#477, #1697 becoming #421.
As built, #1641 weighed 184,870 lbs, 160,570 lbs on its 57” drivers. The driver wheelbase was 15’ 3” and the engine wheelbase 23’ 11”. Fitted with Stephenson valve gear and
15½” x 30” high pressure cylinders and 26” x 30” low pressure, it had a 33.9 sq ft grate and 247.2 sq ft firebox. With a total heating surface of 2,502 sq ft and operating at a boiler pressure of 200 psi, it delivered 31,719 lbs tractive effort. The tender weighs 115,798 lbs light and has a capacity of 6,000 gallons of water and 11 tons of coal.
Like all of the other Vauclain compounds bought by the Union Pacific in the early 20th Century, the 1640s were soon converted to simple expansion locomotives. The main advantage claimed for compounding was lower fuel and water consumption.
Sometime later, the UP added a 417 sq ft Schmidt superheater, removing 136 small tubes in favour of 28 flues, but little else changed. The engine weight rose to 187,891 lbs, 163,205 lbs on the drivers. The firebox dropped to 191 sq ft and total heating surface to 2,436 sq ft. However, tractive effort rose by 20% to 39,458 lbs.
Many of 420 Class worked into the 1950s. #421 was donated to the City of Fairbury, NE, in 1956 and is on display in Fairbury City Park. You can see other 420s on the UP #423, UP #460 and UP #477 pages of this website.
However, the Vauclain arrangement produced uneven forces and excess wear at the crosshead, which increased maintenance costs and largely offset any fuel economies. The complex valve assembly and the starter valve, which allowed admission of high pressure steam directly to the low pressure cylinder, also increased maintenance costs.
In 1918, the low pressure cylinders were removed, the high pressure cylinders enlarged to 21” x 30” and the Stephenson valve gear was replaced with Walschaert valve gear.
#421 is coupled to Union Pacific Class
CA-13-4 Steel Caboose #24626, built in 1971 for the Rock Island as #17208. It was bought by the UP after the Rock Island ceased operations in 1980.
Retired in September 1985, it was donated to Fairbury in 1987.
