The Straßenroller, or road roller, colloquially known as a "Culemeyer", is an item of intermodal transport equipment that permits the carriage of fully-loaded rail wagons and heavy loads on roads.
In the late 1920s the Deutsches Reichsbahn was seeking innovative ways to respond to the increasing demand on the national rail transport system, as well as respond to competition posed by the motor vehicle. Doctor Johann Culemeyer, a senior administrator of the Reichsbahn’s equipment department, proposed development of a wheeled, articulated platform on rubber-tyred wheels that could transport fully-laden railway wagons from a railway siding directly to a customer’s facility without the need for construction of separate rail spurs to link the two locations. This was seen to offer significant cost savings to both the railway and to potential customers, and opening an untapped market for the carriage of goods by railway.
Development of an acceptable design for the transport vehicle itself, and for the ancillary handling equipment, took some time, and it was not until 1931 that a patent for the basic vehicle was obtained, and it would not be until 1933 that the straßenroller system could be demonstrated to the Press and to potential customers. The debut of the system was in April 1933, in Berlin, with the promotional slogan "Die Eisenbahn ins Haus". The first regular shipment of freight wagons by straßenroller began in October 1933, and it quickly demonstrated its popularity in service. At the outset movements were at the rate of thirty wagons per week; after a few months this had risen to ninety wagons per week; by 1938 straßenroller platforms were moving more than 200,000 wagons per year, for more than forty regular customers. In addition to rail cars, the straßenroller system was very much suited for carriage of boilers, heavy machine tools, transformers, locomotives and steel girders.
The first straßenroller were of the R40 type, two articulated frames each with two axles and eight solid-rubber tyres. The frames were adjustable between loading and transport heights, and it had a load limit of 31 tonnes; from 1935 the adjustment feature was removed from the design, which permitted the load capacity to be increased to 40 tonnes.
In 1935 a larger design, the R80 type, was placed in service. It too comprised two articulated frames, each supported by twenty-four tyres. It was designed with a load capacity of 80-tonnes, but from 1938 design improvements allowed the load limit to be increased to 100-tonnes.
Under development at this time is the R42 type, a single-unit straßenroller with twelve tyres, suitable for loads up to 40-tonnes.
For safety reasons the speed limit of the straßenroller is limited to twenty-five kilometers per hour. Each unit is fitted with a combination air/hydraulic braking system, double leaf-spring suspension system and mechanical system. The Reichsbahn has contracted with the Gothaer Waggonfabrik to manufacture straßenroller to its patented design. To date more than two hundred and fifty straßenroller have been constructed, and production is continuing.