Updated: 26 Jan 2006
There have been very few attempts to drive locomotives by means of propellors. One advantage is that forward thrust does not depend on adhesion between wheels and rails. A corresponding disadvantage is that a propellor does not give a positive drive; it is working in a fluid medium so there is an inevitable loss of efficiency. The significance of this loss is something I have not worked out yet.
A GERMAN PROP-LOCOMOTIVE: 1919
Left: A German Prop-Locomotive.
Until recently this project was believed to be Russian, but that is not the case and I apologise for the previous misinformation.
In fact the picture shows a test prototype of the "Dringos" locomtive, patented by Dr.-Ing. Otto Steinitz (front left in the photograph) and assembled under license by the Luftfahrt Company in Grunewald, a suburb of Berlin. It had an aero engine and a two-bladed propellor at each end. The locomotive made its first successful test run on May 11, 1919 from Grunewald to Beelitz, about 30 miles there and back, carrying various government railway officials and parliament members - about 40 people in total. The locomotive easily sustained a speed of 60 mph, limited mostly by concerns about the primitive chassis and braking system of the prototype.
The exhaust stub of the engine at the other end can be seen top right against the gantry.
Unfortunately no detail is visible in the dark parts of the photo, but a little information can be extracted from the picture. The engine is a six-cylinder in-line model, with a total absence of silencing on the exhaust stub. One thing that can be asserted with confidence is that this was not a quiet machine.
The test locomotive was built from an old railway freight wagon using a aircraft engines originally contracted for military use. Part of the motivation for this scheme was finding an acceptable civilian use for these engines that had been contracted for the war effort. Subsequent post-WW1 requirements that Germany destroy its stockpile of and manufacturing capacity for military aircraft parts were definitely a factor in diminishing the interest of the corporate backers - the engine manufacturers. The government railroad interests apparently had little enthusiasm for the concept all along.
It is notable that this project was at least ten years ahead of the more widely known Berlin-Hamburg trials of the
Krukenberg propellor locomotive. (see below)
This information was most kindly provided by Michael Steinitz, the grandson of the inventor.
THE BENNIE RAILPLANE: 1929
Left: The Bennie Railplane.
The Bennie Railplane was a streamlined coach powered at each end by an electric motor driving a four-bladed propeller. Each motor was rated at a continuous 60 bhp.The railplane was a monorail, suspended from a single rail above, with a stabilising rail below. The projected cruising speed was up to 120 miles per hour. Braking was partly by means of the overhead wheels, assisted by reversing the rear propellor. It was patented in 1921.
In 1929-30 a test track about a quarter of a mile in length was built over an LNER line at Milngavie, on the outskirts of Glasgow. Many successful tests and demonstrations were made, but no investors were forthcoming. The track was dismantled in 1941 as part of the WW2 scrap metal campaign, and sadly George Bennie died in obscurity in 1954.
This remarkable machine is a popular subject on the Web, and searching on "Bennie Railplane" will bring up far more information than there is space for here.
THE RAIL-ZEPPELIN: 1931
Left: The Rail-Zeppelin.
The schienenzeppelin (ie the rail zeppelin) was a prototype propellor-driven light-weight railcar that held the world railway speed record for no less than twenty years. It was powered by a BMW aeroengine, driving a four-blade wooden pusher propeller. On June 21, 1931, it kept up 230 km per hour for about 20 km. It was designed by Franz Kruckenberg. Like the Bennie railcar, it never went into production, possibly because of the obvious danger of combining a propellor with a platform-full of passengers.
The propellor axis was angled down by 7.5 degrees to make sure there was a downward force on the track.