In March 1918, the Norfolk and Western Railway (N&W), which had been experimenting with Mallet locomotives to satisfy their growing mainline coal traffic over the Blue Ridge Mountains, introduced Y2 class 2-8-8-2 No.

[7][8] During this time, the United States Railroad Administration (USRA), which was created to control and standardize North American railroads during World War I, assigned the N&W, the Virginian Railway, and the Chesapeake and Ohio Railway (C&O) to their Pocahontas Region, with N&W president Nicholas D. Mahler serving as the regional manager.

[9] Other features the USRA design came with included the Type A Schmidt Superheater, the N&W-style short frame Baker valve gear, and smokebox-mounted air pumps.

2000-2044) of the USRA design in February, April, and May of 1919 from the American Locomotive Company's (ALCO) Schenectady Works, and the railway classified them as Y3's.

[1][3] While the N&W was also allowed to continue ordering 1700 series Y2 class locomotives, the N&W was satisfied with the Y3's superior performance, since they were able to travel with more reliable counterbalancing.

[1][12] Towards the end of the 1920s, the N&W began rebuilding and modifying all their Y3's and Y3a's; their air pumps were moved to the right side of the boiler; they were equipped with a Worthington BL feedwater heater on the left side; and their boiler pressure was raised to 270 psi (1.9 MPa), resulting in their tractive effort being boosted to 136,985 lbf (609.34 kN) with simple expansion and 114,154 lbf (507.78 kN) with compound expansion.

[3][16] During World War II, the N&W sold several of their surplus steam locomotives, including seventeen Y2's, nineteen Y3's, and all the K3 class 4-8-2's, to other railroads in need of extra motive power to help assist the wartime shipments.

1790-1797's performances; while they were able to assist longer trains at Raton Pass, the locomotives' slow speeds made them incompatible with the Santa Fe's fast-moving operations.

[18][20] The Virginian purchased the former Y3's to replace their aging 2-10-10-2's, and the USE's were assigned to pull the railway's heavy coal trains over the Clark's Gap ruling grade.

[18][20] The UP assigned their five 2-8-8-2's to operate around Green River and Rock Springs, Wyoming, and while they were shown to be successful in stop gap purposes, they were quickly deemed surplus, since the UP's 4-6-6-4 "Challengers" and 4-8-8-4 "Big Boys" were more powerful and reliable.

2080-2089 were classified as Y3b's, since they were heavier at 567,000 pounds (257,000 kg) and came with some different design features from the Y3's and Y3a's; their air compressors were always mounted on the left side of the boiler; they were built with Worthington BL feedwater heaters; and their tenders held different capacities—23 short tons (46,000 lb) of coal and 16,000 US gallons (61,000 L) of water.

[25] In October 1927, the Y3b's were all reclassified as Y4's, and in later years, they received some modifications to improve their performances; their boiler pressure was boosted from 240 psi (1.7 MPa) to 270 psi (1.9 MPa); their driving wheel diameter was increased from 57 inches (1,400 mm) to 58 inches (1,500 mm); and they received larger tenders that carried 26 short tons (52,000 lb) of coal and 18,000 US gallons (68,000 L) of water.