Norfolk & Western 2156 - Historic Significance

Historic Significance

Norfolk & Western 2156 is the sole survivor of the railroad's Y5, Y6, Y6a, and Y6b classes (in final form referred to as the "Improved Y5/Y6 class"). These locomotives were among the hardest-pulling steam locomotives ever built. They were originally rated for a tractive effort of 152,206 pounds-force (677.0 kN), and improvements in the 1950s resulted in most of these locomotives (including N&W 2156) having their tractive effort increased to a measured 166,000 pounds-force (738.4 kN), which necessitated adding about 28,000 pounds (12.7 t) of lead to the front engine frame, to improve traction. (By comparison, the famous Union Pacific Big Boy locomotives developed 135,375 pounds-force (602.2 kN) of tractive effort.) This pulling power is all the more remarkable insofar as the only successful steam locomotives that developed somewhat more tractive effort, the Virginian AE class 2-10-10-2s, pulled trains at about 8 mph (13 km/h), while the N&W Y6’s regularly pulled trains 50 mph (80 km/h), and some anecdotal evidence exists that they pulled trains successfully up to 63 mph (101 km/h).

N&W 2156 is also one of the Y6a's that received a new firebox with an extended combustion chamber of the type used on the Y6b class, which increased drawbar horsepower from 4400 hp (3.3 MW) at 20 mph (32 km/h) to 5600 hp (4.2 MW) at 25 mph (40 km/h).