Road–rail vehicle
A vehicle on caterpillar tracks rather than road wheels, which allows mode change anywhere without the need to use a level crossing, has been proposed and modelled by Chinese engineers.
An early promoter of the road-rail system was Brigadier General Robert Stronach, part of a company called Roadrails Ltd formed around 1920.
[7] The idea was that rails offered less rolling resistance while roads offered greater tractive effort, and the combination would allow either greater loads to be hauled, or loads to be hauled on steeper gradients thereby reducing a major cost of building a railway.
[8] One problem with the road-rail tractor was reversing while on the rails, but the ability to raise the bogie and swap to road mode allowed it to run round the train.
A 'Road-rail' branch was built in South Africa, and this used two road-rail locomotives, both converted from steam traction engines.
In the end the experiment was unsuccessful and the branch reverted to normal steam engines by about 1927, and Roadrails Ltd was closed down around the same time.
In the early 1940s, the engineer Talon developed a system in which a normal street bus ran on rails and was able to pull a light Decauville railcar sidecar.
At least one of these vehicles powered by wood gas was used in the summer of 1943 on the 54 km (34 mi) long railway line from Carcassonne to Quillan.
[22] The Deutsche Bundesbahn operated buses, called the Schi-Stra-Bus [de], that could be fitted with separate bogies in different areas from the 1950s to 1970s.
In 1983, the Greater London Council considered investing £230,000 into the Lucas rail-bus, which could run on roads and rail tracks.
[25] The enthusiasm arose from the opportunity to cut costs on rail vehicle production by partially integrating bus parts.
[25] Railroad buses were also developed in Japan, by JR Hokkaido in 2002, under the name DMV (Dual Mode Vehicle).
[26] The DMV920 model no longer used external bogies; the two axles that are carried along are only lowered on the single rail.
[29][30] In 2022, SNCF has presented the concept of FLEXY, a road-rail fully electric autonomous shuttle for areas of low population density.
[33] Evans seems to have produced all road–rail vehicle adaptations for the US military during WWII, but was rapidly overtaken by Fairmont immediately post-war.
[34][full citation needed] UK-based Permaquip manufactures highway-based road rail vehicles, trailers, and attachments.
Their products are known for the automatic locking / unlocking feature and for the rubber spring induced downforce applied to the rails.
[6] Vollert Anlagenbau GmbH has developed a unmanned road-rail remote controlled vehicle VLEX for shunting up to 300t.
The Canadian company Brandt has also converted large truck tractor units for use as locomotives that can move by road to where they are needed.
Road–rail vehicles also serve as motive power for shunting (switching), the process of sorting items of rolling stock into complete trains, or the reverse.
In Australia, similar vehicles are built by Aries Rail using Volvo loaders and AUSA telehandlers.
[citation needed] Road–rail vehicles, particularly those used for inspection purposes, have been involved in a number of serious incidents, including deaths.
[citation needed] In the UK, technical requirements for road–rail vehicles are the subject of a Rail Industry Standard (RIS-1530-PLT).
When operating in road-going mode, drivers have to remember that the dynamics of the vehicle will be changed due to the increased weight at the front and rear of the chassis.
Some manufacturers have developed systems that allow the rail wheels to be stored almost entirely inside the original bodywork thus moving the centre of mass closer to the road axles.
