The French FT was by far the best Tank coming out of WW1, and it also spawned numerous variants. One of them was the Char Renault TSF, a radio cum command tank. The Char TSF (télégraphie sans fil – telegraph without a wire) was called for by General Estienne when the big order for 2500 Renaults was placed in the Autumn of 1917. It was intended as a command vehicle to provide contact between units and with their headquarters or supporting arms or as an observation vehicle. The number of signal tanks required was originally 200 but this was later increased in early 1918 to 470. The thought was to equip every FT batallion with a section of 6 of these radio tanks.
All the mechanical details of the Char TSF were the same as those of the FT combat tanks. In the signal vehicle the crew was increased from two to three men: driver, radio operator and observer/commander and the turret was replaced by a fixed armoured superstructure, equipped with a cupola on top, an observation window in front and a periscope, and housed the radio set. In the prototype vehicles the superstructure overhung the hull sides but in production tanks this was modified so that the hull itself did not have to be modified.
At the start of WW2 the TSF was long since obsolete, and the superstructure of many of these ended up as observations posts in the Maginot Line.
The Char TSF hull below is - to my knowledge - the only one in existance. It is an empty hull, the superstructure originally found in the remnants of the Maginot Line, and (?) now waiting for reconstruction in the fabulous Tank Museum in Saumur in France. The photos have been taken by Eric Gallaud.