The 4-8-2 type was first used on the Chesapeake & Ohio to haul heavy passenger trains through the Allegheny Mountains, and was usually known as the Mountain type. The New York Central, however, was proud of its famous "Water Level Route" between New York and Chicago, via the Hudson and Mohawk valleys and through the Great Lakes region. When it took delivery of its first 4-8-2s, it chose to call them Mohawks instead of Mountains. Eventually the New York Central ordered 600 Mohawk type locomotives in classes L1 through L4. A few of the earlier ones seem to have been retired before the last group was delivered in 1944, but in 1940 there were still 135 members of class L1 on the roster.

No. 2560, shown here at an unknown location, was a member of class L1b, one of the earlier groups ordered by the railroad and delivered by the American Locomotive Company in 1917-18. These engines had 69-inch drivers, a boiler pressure of 200 pounds per square inch, and 28x28-inch cylinders. No. 2560 weighed 364,000 pounds and developed a tractive force of 54,080 pounds; a booster added 11,000 pounds. Like many steam locomotives, No. 2560 and her sisters went through extensive rebuilding and fitting with new appliances; the Elesco bundle-type feedwater heater and the one-piece cast trailing truck, with booster, were not original equipment. The headlight shown in this 1930-era photo was also probably replaced later. The L1 class was used almost exclusively in freight service, as the footboard pilot of No. 2560 reveals.