Propeller Driven Railways

A locomotive can derive power from many different sources. The earliest locomotives were driven by steam. Then came electric trains powered by galvanic cells. Later, onboard batteries were replaced by overhead lines. There are locomotives that run on internal combustion engines that drive the wheels of the locomotive directly using mechanical transmission like in automobiles, or use the rotational energy of the engines to generate electricity, which in turn run the traction motors.

There are also locomotives that run on compressed air, known as “fireless locomotives”, and steam-diesel hybrids (where water in the boiler is heated using diesel fuel instead of traditional coals) and electric-steam hybrids (where water is heated using electric heaters). Some of these unconventional designs have found use in very specific cases, such as in Switzerland, where there are no natural reserves of coal. But one design that failed to gain traction despite showing much potential was the propeller-driven locomotive.

Aerowagon

The first propeller-driven railcar was the Aerowagon designed by Soviet engineer Valerian Abakovsky in 1917. It resembled a horse-drawn wagon but with a large twin-blade propeller attached to the front in place of the horse. The Aerowagon was capable of reaching speeds up to 140 kilometers per hour, but clearly Abakovsky pushed the limits of the wagon’s design to handle speeds. On 24 July 1921, while travelling from Tula to Moscow, the Aerowagon derailed at high speed killing seven of the 22 passengers on board. Among the dead was Valerian Abakovsky.

Schienenzeppelin

Eight years after the tragic accident, German aircraft engineer Franz Kruckenberg designed a vastly improved propeller-driven railcar called the Schienenzeppelin, or rail zeppelin, because it resembled a zeppelin. At the rear was a large propeller that pushed the railcar to unprecedented speeds. The Schienenzeppelin still holds the record for the fastest propeller driven rail vehicle.

The car was 25 meters long and 2.8 meters tall. It was powered by two conjoined BMW IV 6-cylinder petrol aircraft engines driving a four-bladed, fixed pitch ash propeller. Later, the engines were replaced by a single BMW VI 12-cylinder of 600 horsepower and the four-blade propeller was replaced by a two-bladed one. The Schienenzeppelin was built of aluminum to reduce weight, and featured a streamlined body to cut air resistance. The interior was spartan with seats for 40 passengers.

The Schienenzeppelin regularly exceeded speeds of 200 km/h, with the record of 230 km/h set in 1931 on the Berlin–Hamburg line between Karstädt and Dergenthin, which was not surpassed by any other rail vehicle until 1954. The railcar still holds the land speed record for a petrol powered rail vehicle.

The Schienenzeppelin lasted only five years, and only one vehicle was built. The most obvious drawback of the Schienenzeppelin was its inability to pull additional wagons to form a train. Some expressed concern about the dangers of having an open propeller in crowded railway stations. The vehicle also could not climb gradients.

The Schienenzeppelin was sold to Deutsche Reichsbahn (German Imperial Railway) in 1934, and five years later, in 1939, with Germany at war, the rail zeppelin was scrapped and its materials reused by the military.

Bennie Railplane

Around the same time Valerian Abakovsky was experimenting with Aerowagon, Scottish engineer George Bennie began work on his version of a rail-aircraft hybrid. Bennie’s design consisted of a monorail hanging from an overhead track, and propelled by propellers. In 1929-1930 he built a prototype on a trial stretch of track over a 119-metre line at Milngavie, off the Glasgow and Milngavie Junction Railway, and one railplane car to demonstrate the system to potential clients. Bennie believed his Railplane could run above conventional railways, carrying passengers while slower freight traffic moved along the ground. To impress the potential investors, Bennie fitted the demonstration carriage luxuriously fitted with plush carpeting, curtains, comfortable seating, tables and table-lights.

Despite the interest shown around the world, Bennie could not obtain the financial backing he required to develop his revolutionary transport system. In 1937 Bennie went bankrupt, for he had financed most of the work out of his own pocket.