De Dietrich-Schwander

This site is dedicated to the research project conducted by Erwin Schwander at De Dietrich based on his experiences he acquired at Henschel & Sohn in Kassel Germany.


An overview

In 1934 plans were made to develop a new generation of De Dietrich steam railcars, in August of 1934 De Dietrich hired Erwin Schwander, who studied at the Technische Hochschule in Berlin and worked previously at Henschel und Sohn in Kassel, Germany. Here he learned about water-tube steam boilers and steam engines for road vehicles from Abner and Warren Doble, who worked from 1931 until 1934 at Henschel developing steam-powered buses and trucks. Erwin Schwander moved to the Alsace from Kassel to flee the rising power of the Nazi party, his family originated from the Alsace.

The Schwander boiler, which is based on the work of Abner and Warren Doble, is very compact, it has a single water tube, increasing in diameter, which contains a small amount of water, around 27 liters. Due to the close proximity to a big heat source, the boiler reaches working pressure in just 3 minutes and delivers steam at a maximum pressure of 100 Bar. This gave the 2 cylinder double acting compound steam engine a performance of 80 horsepower. The steam engine was integrated with the rear axle, this is similar to the designs of and cars built by Abner Doble and this design is also used by Henschel, in their vehicles.

To aid in the development there were 2 prototype vehicles build, the first in 1934/35 and the second in 1937. The first prototype covered around 10.000 kilometers over a period of 2 years without any major breakdowns. The second prototype was built on a Bugatti Type 46 chassis, which had a steam engine that developed 160 BHP, compared to the Bugatti engine with 150 BHP. Both power and performance were very similar. The second prototype covered over 40.000 km, its range was limited to 250 km due to the amount of water carried. It was capable of reaching 140km/h and over, this was higher than a comparable Bugatti Type 50 but similar to Doble F 35 which was owned by Oscar Henschel.

Further developments of both cars and railcars were halted due to the outbreak of the Second World War. Both prototypes were destroyed during bombings in 1944 during the liberation of the Alsace.

After WOII a single railcar was built but there was no commercial interest from the French railways. Stationary boilers based on the design of Erwin Schwander were sold quite successfully.


Below is a link to a set of drawings of the boiler and the drive-unit of the second prototype. The set is mostly complete. These drawings are kindly made available by the De Dietrich Association, who are custodians of the archive of the De Dietrich Company.

all the drawings as a zip file:

Alles over Hanomag, Henschel & Hanomag-Henschel