Alaska Railroad 4-8-2 "Mountain" Locomotives in the USA

Class M-t/801 (Locobase 5094)

Data from [] (visited December 2002; later rvised as [], last accessed 6 May 2023); and [], last accessed 6 May 2023. (Thanks to Chris Hohl for his 4 April 2023 email noting the booster, variations in the heating surface areas.)

Small Mountain for this northernmost American railroad. Indeed, it is one of only three North American standard gauge 4-8-2s in Locobase with an adhesion weight under 200,000 lb. (90,719 kg).The others are the 1914 Canadian Pacific I1 class found in Locobase 4258 and the New Orleans Great Northern 200 at Locobase 6909).

Firebox had three thermic syphons (84 sq ft/7.80 sq m) and a combustion chamber (64 sq ft/5.95 sq m), which together contributed 148 sq ft (13.75 m) to the firebox heating surface area. Its Simplex Type BK mechanical stoker (first on the railroad) and the trailing truck booster were two prominent mod-cons.

Built at Eddystone, the engine was taken apart and shipped up to Anchorage, where they were reassembled in the shops. 801 (works number 61736 in May 1932) was completed in 1932. At the time of its delivery, Baldwin published a description of the 801. In later years, the ARR site prepared diagrams and data pages. Baldwin's report gave the count of 2 1/4" tubes as 192 and total heating surface area as shown at 2,991 sq ft. ARR's two diagrams specified 181 tubes and a total heating surface area as 2,870 sq ft (266.63 sqm)

Yet when Locobase used the 192 tube count in Baldwin's 1934 report, the tube area calculation generates a higher total evaporative heating surface area than the builder gives in the same report. Using the 181 count from the two diagrams, however, yields a nearly exact match.

It was wrecked twice, once in 1942,, which resulted in an extensive rebuild. and once in 1950.

802 (works number 64366) entered service on 5 December 1942 and ran until dieselization led to its retirement and scrapping in April 1954.