The two vehicles, designated DET 1 and DET 2, were the first operational railcars in Europe to be powered by a diesel engine. Although they were developed at the request of the Saxon and Prussian State Railways, they only stayed in Saxony until testing was complete and spent the rest of their lives in Switzerland. The sister series of the DET were three Prussian railcars with the designations VT 101 to 103, which were phased out immediately after their testing and soon thereafter retired.

In order to distribute the weight of the railcars as evenly as possible, the diesel engine and the electric drive unit were placed on opposite ends of the vehicle. The engine from the Swiss company Sulzer and the associated generator were located in a hood in front of the front driver's cab and rested on a non-powered, three-axle bogie. The electric motor was housed in the rear bogie, which drove the two axles via a jackshaft and rod.

The car body, including the driver's cabs, was strongly reminiscent of the four-axle passenger cars of the time. As is common today with road vehicles, the heat from the cooling water from the engine was used to heat the interior. The interior lighting was already electric, and four of the five axles were braked using air brakes.

The two vehicles were delivered to the Saxon State Railways in 1915 and tested primarily on the Dresden-Döbeln-Leipzig route. However, after it was no longer used as planned due to the war, it was brought to Switzerland for a demonstration in 1922, where the planned sale to the SBB did not take place.

Instead, they came to the Régional du Val-de-Travers in the canton of Neuchâtel, where they would remain in service for a long time. In 1938, one vehicle was handed over to the SBB for refurbishment after severe damage. However, this refurbishment was not carried out due to the war, so that this vehicle was scrapped in 1948. The other vehicle was retired until 1965 after a defect and is now on display in the Swiss Museum of Transport in Lucerne.