The French Decauville X 52103 railroad automotor from 1945.
The SNCF X 52100 class are diesel railcars that operated on the alpine lines from Grenoble, France from 1945 until 1973. They were capable of multiple unit operation with other car types, requiring an operator in each car; the lead conductor giving acceleration or deceleration orders using an audible tone.
These were the first diesel-electric railcars used by the SNCF.