Tractive Power Corporation TP56

These are N scale 3D printable files for the Tractive Power Corporation TP56 — one of the most unusual and intriguing locomotive prototypes in North American railroad history, and a subject virtually absent from the commercial model railroad market until now.

The Tractive Power Corporation (TPC) was a small Arizona-based manufacturer that developed the TP56 in the late 1970s and early 1980s as a radical alternative to the conventional diesel-electric locomotives dominating North American railroading. Rather than the standard arrangement of a large prime mover driving electric traction motors, the TP56 used a diesel-hydraulic transmission — a technology common in European practice but largely rejected by American railroads after unsuccessful experiments by manufacturers like Krauss-Maffei in the 1960s. TPC believed that advances in hydraulic transmission technology had overcome the earlier reliability problems, and that a diesel-hydraulic locomotive could offer significant advantages in fuel efficiency, weight, and mechanical simplicity over the diesel-electric giants from EMD and GE.

The TP56 was a switcher locomotive with its engine and body mounted directly onto a repurposed EMD SD40-2 C truck — the same rugged three-axle powered truck used under one of the most successful mainline locomotives in North American history. This pragmatic approach gave TPC a proven, readily available running gear foundation while keeping costs down, and resulted in one of the most unconventional-looking switchers ever to operate in North American service. Designed for industrial, yard, and short line switching duties where the massive horsepower of a mainline locomotive was unnecessary and uneconomical, its compact size, relatively low purchase price, and promised fuel savings made it an attractive proposition for smaller operators struggling with the economics of 1970s-era railroading. A small number of units were built and operated, making the TP56 one of the rarest diesel locomotive types ever to turn a wheel in revenue service in North America.

Powering your model: a community-developed guide to mechanism options for the TP56 is available at The Railroad Wire forum.

After purchase, your digital files will be available for immediate direct download from your order confirmation. These files are for Personal Use Only — if you are interested in a commercial license, please contact us.

Please allow a few weeks for 3D printing and shipping.