Trainsurfers in Russia.
This fun is very common in the Moscow region and to a lesser extent in St. Petersburg.
In other regions of our vast country trainsurfers practically does not occur. They are surfing ER2R 3 kV DC EMU train (max speed - 130 km/h) on this photo. ER2R EMU trains were produced by Riga Carriage Works between 1979 and 1987. In total there were produced 89 units in different numbers of cars (from 4 to 12). Now most of ER2R are taken out of service in Russia, but you can see ER2R in Ukraine.