2-8-8-8-4

Other equivalent classifications are: Only one 2-8-8-8-4 was ever built, a Mallet-type for the Virginian Railway in 1916.

The XA was unable to sustain a speed greater than five miles an hour, since the six cylinders could easily consume more steam than the boiler could produce.

When operating in compound the high pressure steam was divided between the cylinders of the center engine.

The exhaust from one cylinder was piped to the front articulated engine.

The tender had a four-wheel truck at the rear to help guide the locomotive into curves when drifting back downhill after pushing a train over the hill.