- Quantity Built: 16
- Locomotive and Tender Combined Length: 114’ 10.5”
- Weight: 582,900 lbs.
- Horsepower: 5600 hp at 25 mph
- Boiler Pressure: 300 psi
- Speed: 50 mph
- Trucks: 2-8-8-2
- Tractive Effort: Compound—127,000 pounds-force (lbf)/Simple—152,206 lbf
- Driver Diameter: 57” original, 58″ modified
- Norfolk & Western (N&W) Y6a 2156 was built in the Roanoke Shops in March 1942.
- N&W began converting to diesel-powered locomotives in the late 1950s and the Y6a #2156 was retired from service in 1959.
- It is the only remaining locomotive of the Y5, Y6, Y6a, and Y6b classes.
- While cosmetically restored, 2156 is no longer operational.
- On loan from the Museum of Transportation, St. Louis, Missouri
Class Y6 Description
These compound articulated (Mallet) locomotives were among the hardest working steam locomotives ever built. The Mallet design allowed these large locomotives to be used on track with tighter curves by splitting the driving wheels into two sets which can turn independently. They also improved efficiency by using steam from the boiler twice, once in the smaller (high-pressure) cylinders to power the rear driving wheels and a second time on the larger (low-pressure) cylinders for the front drivers.
The Y6 design was improved after World War II in the Y6a (and later Y6b) classes. The driver wheel size was enlarged, allowing for longer tire life. The sand pipes were covered, the tender was streamlined, the coal bunker was enlarged, and the water tank got a flat top without a decrease in capacity. These changes increased efficiency and helped the Y6 continue in main-line service while many railroads were converting to diesel locomotives.
Norfolk & Western used 2156 and the other Y6-class locomotives primarily for heavy freight trains and coal trains in the mountainous areas of Virginia and West Virginia. Although they were used throughout N&W, their primary work occurred on the Pocahontas, Radford, and Shenandoah Divisions. When diesel locomotives took over mainline steam operations, the Y6-type locomotives spent their last years primarily on mine and coalfield runs.