This railcar is named after its inventor Georg Thomas, who was director of the Hessian Ludwigsbahn and thought about the most efficient vehicle possible for passenger transport. The double-decker vehicle, with its well-engineered and forward-looking design, was soon able to find several buyers, but mass production was ultimately denied.

Although the railcar looked like one piece at first glance, it was actually a combination of a single-axle power module and a two-axle passenger car. These two parts could only be separated from each other in the workshop, but the patent also explicitly provided for the use of the rear part as an independent car. In the lower part there were compartments of all three classes and in the upper part there were only third class transverse benches. To make the best use of space, the boiler was mounted across the rear of the driver's cab and the power was transmitted to the cranked axle by cylinders mounted under the floor.

The power was sufficient to be able to pull up to three cars. The coal was also stored inside the driver's cab and the water supplies were located under the floor of the passenger compartment to save space. Although there was also a cable on the rear platform to operate the whistle, normal driving was only possible in one direction. Reaching the driver's cab via the roof and a roof hatch was intended in the design, but can only be seen as an emergency solution. This meant that the railcar had to be rotated at the end of the line to change direction.

Despite the predicted great future and the sales to several railway administrations, this vehicle did not prove itself and thus all locomotives were retired around the turn of the century.