James O. Allis DM6 (Legions of Steam 2023)/Behind the Scenes

Background Information
The James O. Allis DM6 (also known as the JALC DM6 and JACO DM6) is a fictional standard gauge diesel locomotive built by the fictitious James O. Allis Locomotive Company of Philadelphia, Pennsylvania. According to the tie-in "Locomotive Handbook" the DM6 was purported to be built as 100 examples, of which 40 survive as of 2022.

The James O. Allis DM6 is based on a Shay Class B two truck logging locomotive built by Lima Locomotive Works of Lima, Ohio. The DM6 however differs from a conventional steam powered Shay in that whilst the DM6 had a three cylinder "motor," it utilizes internal combustion instead of steam pressure. More specifically, this power unit uses the diesel cycle where power is caused by mechanical compression of fuel oil (or diesel fuel) rather than the expansion of steam.

Gauge 1 model
The DM6 locomotive was custom built for the film as multiple Gauge 1 models. All models were essentially kitbashed, using a Märklin locomotive as a donor for the chassis and various parts. The motor unit had a fully enclosed "crankcase" which avoided the cost of custom machining a crankshaft and made production a lot easier. It was sculpted out of PVC.

Each DM6 had their wheels and trucks sourced from a DB Class 294 gauge 1 diesel locomotive made by Märklin. The right side of the class 294 trucks were modified to accept a set of bevel gears that were custom machined. The driveshaft was also machined, being supported by roller bearings integrated into the PVC "motor".

The cab, running gear assemblies, and toolboxes were sourced from the BR 80. The short and long "hoods" were formed from PVC blocks that were machined. The models also had two exhaust pipes which were plastic tubes glued onto the PVC that were cut from articulated straws and sprayed with house paint. Also, the PVC and Märklin components were painted using off-the-shelf house paint as well.

The models were track powered, so pick-up contacts were attached to the metal wheels, which ran into the motor to power it. The electricity ran from the track to the wheels/pick-up contacts and thus provide power to the locomotives. All but two of the DM6 models used the same cab as the BR 80. One of them had a custom molded plastic cab resembling that of a generic switcher locomotive and a bell, whistle, and custom headlamp covered in gold leaf.