Development of the New York Central's Hudsons culminated in the J3a class, Nos. 5405-5444, delivered by Alco in 1937, followed by the ten streamlined Hudsons a year later. The unstreamlined members of the class weighed in at 360,000 pounds. They had 22½x29-inch cylinders, and carried a boiler pressure of 265 pounds. Although their tractive effort without booster was somewhat lower that that of the J1 class, with booster cut in it was slightly higher at 53,960 pounds. More importantly for the high-speed service for which the J3s were designed, their steaming capacity rendered them capable of 4700 horsepower at 77 miles per hour, compared with 3900 horsepower at 66 miles per hour for the J1 class. This was partly due to their slightly larger grate area of 82 square feet. The J3s also had roller bearings on all axles. No. 5405, the first of the 40 unstreamlined locomotives, represents the class in this builder's photo.