After the 185 “Mohawks” of the L-1 class, the New York Central developed the more powerful L-2 class. It was also intended purely for freight service, but had a larger boiler, a feedwater heater and a booster on the trailing axle. The driver diameter remained at 69 inches or 1,753 mm and allowed a maximum permitted speed of 60 mph or 97 km/h.

Production began in 1925 at ALCO in Schenectady with 100 locomotives of the subclass L-2a. Further subclasses up to the L-2d all also came from Schenectady and brought the number to a total of 300 by 1930. They differed in the boiler dimensions, wheelbases and the feedwater heater used, which could be of the Elasco, Worthington or Coffin types.

In 1939, two L-2d were converted as prototypes for the L-3 for mixed service. These were intended to achieve higher speeds without requiring larger drivers. Thanks to roller bearings on the axles, cylinders with a smaller diameter and a higher boiler pressure, they could be approved for speeds of 80 mph.