Class SF-63 (Locobase 80)

Data from table in 1930 Locomotive Cyclopedia. See also DeGolyer, Volume 76, pp. 94+. (Many thanks to Chris Hohl for his 22 September 2017 email reporting unlikely boiler pressure values for 177 entries. A Locobase macro caused the error .) Works numbers were 59196-59197, 59221-59222, 59233-59238 in May 1926.

Boiler had a Worthington No 4 feed water heater mounted on the left side "as low as possible", Standard Stoker Company's Du Pont stoker. Baldwin's specs for the firebox's heating surface area showed a combustion chamber contributing 118 sq ft (10.95 sq m), 94.4 sq ft (9 sq m) of thermic syphons, and 15 sq ft (1.4 sq m) from arch tubes. The firebox also had ten combustion tubes inside, five to each side.(See Locobase 7681 for the smoke-suppressing purpose of these steam-jet tubes.)

The rigid wheelbase for this long engine was 16 ft 6 in (5.03 m). Franklin Railway Company lateral-motion boxes in the front drivers allowed 1" (25.4 mm) of lateral motion to each side.

The specs also comment on a manufacturing error: "In consideration of five engine frames being cut out slightly more than drawings required and the back top fillet in same pedestal being deeper than necessary, the BLW hereby guarantees these frames indefinitely against breakage in the front pedestal because of these errors and in the event these frames fail, the BLW will replace same free of cost to Ry Co. These frames have been accepted and applied to locomotives." 1720 and 1721 had both miscast frames replaced and 1722 got a new left-side frame .

2-10-2s were rare on the MoPac and most operated in hump service at classification yards.

Such were the power demands during World War II, however, that the railroad rebuilt this ten-engine class with lightweight main and side rods, Timken roller bearings on the axles, a trailing-truck booster engine (for which the original specs had made provisions), and a larger tender and put them back out on the road. Boiler was now set at 220 psi (15.2 bar) and starting tractive effort rose to 85,485 lb (38,775 kg) without the booster. The booster added 13,200 lb (5,987 kg) of TE.

The Arkansas Railroad Club's Arkansas Railroader of August 1984 (Vol. 15, #8) p.8 -- archived on [], last accessed 12 January 2010 -- claimed that the rebuild "...made them a true high-speed freight engine and, in the declining days of steam, some were even used in helper service on fast passenger trains on the Missouri Division."

The last was retired in 1955.

Class SF-63 (Locobase 5437)

Data from "Recent Locomotives of the Santa Fe and Consolidation Types" table, Railway Mechanical Engineer (RME), Volume 91, No 1 (January 1917), p. 16. (Thanks to Chris Hohl for his 1 October 2021 email noting the correct cylinder stroke, boiler pressure, and the later use of larger tenders.) Works numbers were 56476-56489 in November 1916.

The Iron Mountain system (St Louis, Iron Mountain & Southern) -- itself an accumulator of smaller lines in the previous decade -- bought these engines while in the receivership that would lead, in May 1917, to its being absorbed by the Missouri Pacific. These Santa Fes were large beasts with long boilers over long wheelbases.

Later in their careers, Chris Hohl found, the class trailed tenders holding slightly less water (9,750 US gallons/36,904 litres), but more coal (19 tons/17.3 metric tons), which caused a weight increase to 196,600 lbs (81,976 kg),. and an increase in the total wheelbase of 2" (50.8 mm).

The last didn't leave the MoPac until 1953.