In 1919, German engineer Otto Steinitz built an experimental carriage with two propeller-driven groups, borrowed from aviation technology. The machine, called Dringos, successfully developed high speed and was of great interest to the railroad. Nevertheless, some features of the Versailles Peace Treaty and the state of German industry did not allow the full-fledged production of new equipment to be mastered. Over the next ten years, German specialists did not return to promising topics.
At the end of the twenties, scientist and engineer Franz Krukenberg became interested in the further future of railway transport. At that time, numerous attempts were made to improve its characteristics, in particular, various methods were proposed for increasing the speed of trains. F. Krukenberg decided to continue the development of the so-called. aeronautical cars - self-propelled cars (railcars) equipped with an aircraft-type power plant, with an engine and a propeller.
The main goal of the project authored by Krukenberg was to achieve the maximum possible speed of movement, for which it was proposed to use some specific technical solutions. Because of them, the promising air car had to have a characteristic appearance, thanks to which its name appeared. According to the author of the project, the new machine looked like an airship, and therefore received the appropriate name: Scheinenzeppelin ("Rail Zeppelin").
All the necessary design work was completed by the end of 1929. At the beginning of the next year, construction of a prototype began at the Hannover-Leinhausen plant. The prototype assembly took several months. It was possible to start the first tests only in the fall of 1930. During construction and shortly after its completion, the project underwent some changes. So, initially, the "Rail Zeppelin" was to be driven by a propeller with four blades, but later it was replaced by a two-bladed one, and in the final stages a wheeled propeller was used. The type of engine also changed.
The dimensions of the Scheinenzeppelin air car were set by the requirements for railway equipment. It had a length of 25, 85 m and a height of 2, 8 m. The curb weight of the machine did not exceed 20, 3 tons. In order to achieve the maximum possible speed, F. Krukenberg lightened the air car by using the appropriate hull design and materials used in it. The body of the machine was made in the form of a frame covered with a skin. Aluminum was widely used in the design. In addition, some weight was saved due to the low "fit" of the case.
The body of the Scheinenzeppelin railcar had characteristic contours with a rounded nose cone. In the tail section, the body was divided into two parts. The power plant was placed in the tapering upper, and the lowering lower was used to improve aerodynamics. A curious feature of the air car was the glazing of the passenger compartment. It was made in the form of a continuous long strip with bindings, but without wide racks-dividers, which gave the car an unusual appearance.
The cockpit was placed in front of the hull. To improve visibility, the crew's workplaces were located above the level of the passenger compartment: the upper edge of the windshield was in contact with the roof of the hull. The entire middle part of the carriage was given over to accommodate passengers. The cabin, designed in accordance with the chosen course of car lightening, was able to accommodate 40 passengers. The upper aft fairing housed the engine and the propeller.
Scheinenzeppelin was originally to be powered by a 250 hp six-cylinder BMW IV engine. A four-blade propeller made of wood was to be mounted on the engine shaft. In the future, the power plant "Rail Zeppelin" has undergone major changes. The car was equipped with a 12-cylinder BMW VI engine with 600 hp. and a two-bladed propeller. It was with such a power plant that the new air car passed the main tests and set several speed records. To create a pressing force, the propeller axis was located at an angle of 7 ° to the horizontal. The chassis of the Scheinenzeppelin machine consisted of two wheelsets with a base of 19.6 m.
In the spring of 1931, the tests of the air car reached the stage of determining the maximum characteristics. So, on May 10, the car developed a speed of 200 km / h, which was a record for both rail transport and ground vehicles in general. On June 21 of the same year, a new record was set on the Berlin-Hamburg line. This time the aerial car was able to accelerate to 230.2 km / h. A new record for the maximum speed of rail transport was set only in 1954. At the same time, Scheinenzeppelin still holds the record for the maximum speed of petrol-powered rail vehicles.
Based on the test results in 1932, F. Krukenberg developed a project for a deep modernization of the existing "Rail Zeppelin" with a change in the mass of the most important units. The chassis has undergone some changes. So, instead of one wheel pair, a full-fledged two-axle bogie was installed in the front of the car. For a number of reasons, it was decided to abandon the propeller, instead of which a fairing was installed on the prototype. Now the engine torque had to be transmitted to the wheels of the front bogie using a hydraulic transmission.
At the beginning of 1933, the updated Scheinenzeppelin entered trials, during which it showed lower performance in comparison with the basic modification. During test runs, it was possible to reach a speed of only 180 km / h. Subsequently, the car received a new Maybach GO5 engine and in this form was planned for deliveries to customers.
According to some reports, the reason for all the changes in the 33rd year and the rejection of the propeller was a number of problems identified during the tests. Indeed, the "Rail Zeppelin" with a propeller-driven group could develop a uniquely high speed, but the features of such a propulsion unit prevented its full use in practice.
The main problem was the open position of the propeller. Because of this, the air car posed a great danger to passengers and railroad workers who were on the apron at the time of arrival or departure. Scheinenzeppelin was no less dangerous when moving along the route.
There were also some technical and operational problems. The aerial car could accelerate on straight sections, but had serious problems with overcoming climbs. In some cases, the power of the propeller group was insufficient to climb the mountain. As a result, to overcome such sections, an additional power plant was required with the transfer of power to the wheels, which increased the weight of the entire machine and, as a result, reduced its maximum speed. At the same time, an additional engine or transmission for wheel drive had to be used from time to time, the rest of the time being a useless excess load.
The characteristic difference between the Rail Zeppelin and other passenger vehicles for the railway was the impossibility of forming trains. The power plant used excluded the coupling of several aerial cars or the combination of Scheinenzeppelin with non-self-propelled ones into one train. In this regard, potential operators of a promising machine would have to form a fleet of their equipment and develop a timetable, taking into account the need to use a sufficiently large number of "Rail Zeppelin", surpassing other trains in speed, but seriously inferior in capacity.
In terms of the totality of its characteristics, the Scheinenzeppelin air car was considered interesting, but without practical prospects. The only prototype built was driven to the manufacturer's site. There, a prototype of the new technology was stored until 1939. The history of this machine ended trite: in the late thirties, Germany was preparing for war and needed a large amount of metal. The only Rail Zeppelin, which used a large amount of aluminum, was dismantled for remelting. By this time, Franz Krukenberg had completely abandoned the idea of using the propeller. All new projects of railway technology developed by him used a hydraulic transmission.
