The Turbotrain was any of several French high-speed, gas turbine trains. The earliest Turbotrain entered service in 1967, for use on France's SNCF intercity lines. There were several versions, four in total, with the last exiting service in 2005, and it is the Turbotrain that made advances possible for the TGV.
In 1967, the SNCF converted a 2-car X 4300 Class diesel multiple unit train originally built by ANF Industrie (Ateliers Construction du Nord de la France) starting in 1963 (either train number X4375 or X4365), into the prototype experimental Turbotrain TGS (Turbine à gaz spéciale). The new gas-turbine engine was installed into the trailer car of this 2-car set; the original diesel power-car was fitted with a new cab but retained its original diesel motor and transmission.
Trials started on 25 April 1967. The TGS reached 252 km/h (157 mph) on 15 October 1971.
This is the first-generation of production Turbotrains. These ETG (Elément à Turbine à Gaz) trains were four carriage trainsets which offered 188 seats and possessed one diesel engine and one gas turbine engine. The gas-turbine engine was a 820 kW Turbomeca Turmo IIIF3 gas-turbine Voith hydraulic (derived from a helicopter turbine) and the diesel was a 320 kW Saurer SDHR diesel-mechanical. These trains reached 160 km/h (99 mph). The ETGs entered service in 1971 on the Paris-Caen-Cherbourg. A total of 14 of these four-car trainsets were manufactured from 1969-1972 by ANF. These trains were maintained at the Venissieux trainshed in Lyon for "many years", but were moved to the Lyon Vaise depot in the 1980s. Electrification of the Grenoble line caused some trainsets to be shifted to work in Clermont Ferrand and Metz.
The UAC TurboTrain was an early high-speed, gas turbine train manufactured by United Aircraft that operated in Canada between 1968 and 1982 and in the United States between 1968 and 1976. (Amtrak disposed of the trains in 1980.) It was one of the first gas turbine powered trains to enter service for passenger traffic, and was also one of the first tilting trains to enter service.
A series of design studies carried out by Chesapeake and Ohio Railway in the 1950s used the second-generation Talgo design for their car suspensions. The suspension arms for each neighboring pair of cars were attached to a common bogie between them, as opposed to having a pair of separate bogies for each car. The bogies rode the common curve between the two cars, centered by traction springs that centered the axle between adjoining car bodies. TurboTrain cars are 2 1⁄2 feet (76 cm) lower than conventional cars, to lower the center of gravity in relation to the swinging point at the top of the arms. The arms included air springs to smooth out the motion, although it still felt "odd" while the train navigated short turns in switchyards and stations.