The last set of Mohawk 4-8-2s acquired by the New York Central were the 25 members of class L4b, delivered from Lima Locomotive Works in 1943-44. Like the L3a and L3c classes, the L4 was equally at home in heavy freight or fast passenger service. Many representatives of both classes were later fitted with the "elephant ear" smoke deflectors visible on No. 3137. The L4s carried a boiler pressure of 250 pounds per square inch, and had 26x30-inch cylinders. With 72-inch drivers, they exerted 59,900 pounds of tractive effort. Their evaporative heating surface totaled 4675 square feet and their superheater surface 2100 square feet, and their grate area measured 75.3 square feet. The tender held 43 tons of coal and 15,500 gallons of water, and the total weight of both locomotive and tender was 766,700 pounds.

The L4b was the first New York Central class to feature the multiple-bearing crosshead instead of the "alligator" type still used on the J3 and L3 classes and the earlier L4s. (The multiple-bearing crosshead also appeared on the Niagara 4-8-4s and the P&LE A2 2-8-4s.) By the time I was photographing steam, even these modern Mohawks had been displaced from most of the NYC's main lines and relegated to more lightly traveled lines. No. 3137 had about six months more to run when I photographed her at Mackinaw City, Michigan in August 1955.