A 2-8-8-2 articulated with disc driver centers must be a rarity; I am not aware of any others besides the Western Pacific class M-151 which Baldwin Locomotive Works delivered in 1938, the second group of 2-8-8-2s for the WP. (Of course the later Southern Pacific cab-forward 4-8-8-2s had disc drivers, and might be considered 2-8-8-2s with a four-wheel pilot truck substituting for a two-wheel trailing truck so they could run in "reverse.") The WP's 2-8-8-2s weighed 665,100 pounds and developed 137,174 pounds of tractive force, augmented with a trailing truck booster. With 63-inch drivers, they had a boiler pressure of 235 p.s.i., and their four cylinders had dimensions of 26x32 inches. Grate area totaled 145 square feet, evaporative heating surface 6811 square feet, and superheater surface 2152 square feet. During World War II they were equipped to supply steam heat and occasionally saw passenger service, probably on heavy troop trains. No. 257 represents this second group in a view purchased via eBay, which shows the locomotive in 1938 with rods removed prepared for shipment from the Baldwin works in Eddystone, Pennsylvania. By 1952, with WP's advancing conversion to diesel power, these oil-fueled 2-8-8-2s had been dropped from the roster.