On April 3rd 1934 DSB opened the first S-train line - Frederiksberg - Vanløse - Nørrebro - Hellerup - Klampenborg .
The first trainsets had been delivered during 1933-34 and their number was increased in 1935 and 1936. The trains were built by Frichs in Århus and Scandia in Randers. The electrical equipment was supplied by the English company English Electric Co. and parts for the engines by Thomas B. Thrige and A/S Titan.
In 1936 additional rollling stock was acquired thereby making it possible to operate trains consisting of 4 cars instead of 3. Power for the train came from one of two current collectors operating on 1500 V DC.
The first generation of S-trains in brown livery were in service from 1934 to the 1970's. New trains were delivered until 1962. The last of these trains in regular service drove on the F-line - Hellerup - Nørrebro - Vanløse - Frederiksberg, the last of them were scrapped in 1976.
The second generation of S-trains in red livery were delivered from 1967 to 1977 in time for the opening of the new line to Hillerød. In the beginning a trainset consisted of cars from both Frichs Århus and Scandia-Randers. In 1980 Scandia-Randers delivered four prototype trainsets - the third generation of S-trains. All in all 8 were delivered, but they have now been scrapped.
The batch delivery trains (delivered 1985-1986) have a double set of headlights, thus setting them apart from the prototype trains.
To replace the second generation of S-trains a new fourth generation S-train was ordered in1995. These trains are built by Linke-Hoffmann-Busch/Siemens in Germany. The original order was for 120 trainsets, but this has since been changed to 105 trainsets (8 cars) and 30 trainsets (4 cars).