Western Pacific class M-80

The Western Pacific class M-80 was an oil-fired 2-6-6-2 Mallet introduced in 1917. It had drivers of 57 inches and cylinders with diameters of 23.5 and 37 inches, at a stroke of 32 inches. Five were built in 1917 by ALCO-Brooks and five more in 1924 by ALCO-Richmond. At the beginning they were used in the Feather River Canyon between Oroville and Portola in California.

The firebox heating surface given in the specs is the value after the installation of thermic syphons. Although this increased their power, the M-137 2-8-8-2 introduced in 1931 could haul the same load as a M-80 together with a MK-60 Mikado. After this, the M-80 was used on the Northern California Extension between the Keddie Wye and Bieber. There they worked on until the end of steam on the Western Pacific.