Maybach-Motorenbau quickly realized that when using a new high-speed diesel on the rail, one should not do things by half-measures. Instead of “just” supplying the engine, Maybach wanted to design a railcar in which all the components were the result of a concerted collaboration between the engine manufacturer and a train builder – a form of cooperation that was absolutely exceptional in its intensity at the time.
As early as 1922, two years before the completion of the G 4 engine, the contracts were signed with Eisenbahn Verkehrsmittel AG Berlin, or E.V.A for short, Waggonfabrik Wismar. E.V.A. took over the construction of the chassis and the car, while Maybach also developed the gearbox in addition to the engine.
This was also related to the new requirements that the use of a diesel engine placed on the concept of the railcar. In a steam locomotive, the performance profile is already defined in the design by the number (more wheels with a smaller diameter = higher tractive force) and size (larger wheels = higher maximum speed) of the driven wheels, with an emphasis on either tractive force or speed. The speed is controlled by the amount of steam injected into the cylinders. A diesel engine, on the other hand, requires a gearbox in order to optimally transfer the engine´s power to the rail. Maybach´s answer to this challenge was called T1: a completely independently designed four-speed transmission.
The engine and transmission were already installed in the railcar in Friedrichshafen in the spring of 1924 – in railway jargon also referred to as the wedding.
However, the subsequent test runs in the hinterland of Lake Constance had nothing to do with a honeymoon. “For us it was an exhausting trial and error until we could afford to leave the tracks of the company premises,” Maybach employee Richard Lang recalled later, “and we had to take up the patience of the travelling public again.
And yet the E.V.A.-Maybach railcar, also known as ‘Rohölwagen’ (crude oil railcar), was one of the attractions at the International Railway Exhibition in Seddin, which was attended by 5,000 rail experts from all over the world from September to October 1924. In particular, the engine’s good mass-to-power ratio of 8 kg/hp met with a positive response from experts. However, the car made a less brilliant appearance during a test drive following the exhibition, with a high-ranking delegation from the Reichsbahn of all companies. A heavy engine defect put an end to the journey after a few kilometres. “The mood of the men, most of whom were still very critical of the railcar anyway, was not raised by the fact that the entire company had to walk to the next station on the railway line in pouring rain,” reported Richard Lang.
Despite this breakdown, the Reichsbahn integrated the railcar under the number VT 851, while the VT 852 prototype, which was built shortly afterwards, was equipped with the more powerful G 4b engine. Subsequently, a total of 15 railcars with the designations VT 853-861 and VT 866-871 were used – initially on only a few routes. But Maybach believed in the potential of the new engine type, and this perseverance was to proof its worth in the following years.
Source and also an important reading tip for further reading: Wilhelm Treue, Stefan Zima: High-performance engines. VDI Verlag: Düsseldorf, 1992. The book is available antiquarian. We would like to point out that an extended new edition of the book is planned.
Heinz R. Kurz: The railcars of the Reichsbahn types. EK-Verlag, Freiburg 1988
A G 4b engine on loan from MTU Friedrichshafen GmbH is on display in the foyer of the Karl-Maybach-Gymnasium in Friedrichshafen, at the entrance to the Cinema.
Photos: MTU Friedrichshafen GmbH
1. Maybach railcar gearbox Type T 1
2. Maybach diesel engine Type G 4 in bogie railcar
3. Maybach EVA railcar starting tests Aulendorf 1924 (also banner)