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 around 360,000 pounds. They had 22½x29-inch cylinders, and carried a boiler pressure of 265 pounds. (The pressure was originally set at 275 pounds, but was reduced when it was found that the additional thrust actually caused the rods to bend.) Although the tractive effort of the J3s 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, together with a combustion chamber which the earlier class did not have. The J3s had 4185 square feet of evaporative heating surface and a superheater surface of 1745 square feet. They also had roller bearings on all axles. No. 5405, the first of the 40 nonstreamlined locomotives, represents the class in this builder's photo. It was retired early in 1956.