Pennsylvania Railroad class N1s
The Pennsylvania Railroad N1s was a class of 2-10-2 "Santa Fe" steam locomotives built for the Pennsylvania's Lines West. 60 engines were built between December 1918 and November 1919, and worked heavy mineral freight to and from ports on the Great Lakes until their retirement in the late 1940s. All examples were scrapped by 1950.
Overview
The 2-10-2 wheel arrangement, ten driving wheels with a two-wheel leading truck and a two-wheel cast KW-pattern trailing truck under a large Belpaire firebox, suited the N1s' intended purpose well. They were drag freight engines, designed to haul heavy freight up the 0.3% grade leading out of the PRR's "Lake ports," and were rated at on these relatively easy grades. The design was developed by the PRR's Fort Wayne Shops and orders were placed with Alco and Baldwin for a total of 60; the first Alco locomotive was delivered in December 1918, with the remainder arriving during 1919.The N1s was a large locomotive; the boiler was the largest then used on any non-experimental PRR locomotive, and the firebox had of grate area and a long combustion chamber. No feedwater heater was fitted, but a mechanical stoker and power reverse were installed, being necessities on such a large locomotive. Boiler pressure was initially set at, but was quickly raised to. The boiler was reportedly designed to take a pressure of, but whether it attained this pressure in service is not known.
To allow the locomotive to negotiate tight 22-degree curves, the first and fifth driving axles were fitted with lateral motion devices and the center axle was blind.