To accelerate heavy freight trains, the Erie Railroad ordered 20 class N-1 locomotives from Baldwin in 1911, which were the heaviest Mikados at the time. Since this design was a success, a total of 135 more were ordered, which were also manufactured by ALCO-Schenectady and by Lima. The boiler pressure of the individual locomotives was between 170 and 200 psi.
From 1927 the locomotives were rebuilt, adding a feed water heater, removing some tubes in the boiler and setting the pressure uniformly at 190 psi. Many received a mechanical stoker, but at least 50 remained hand-fired. Almost all were scrapped between 1947 and 1951, few were sold.