The body is made of lightweight stainless steel structure developed in-house by Hitachi, and is designed to withstand the UIC-regulated 200 ton end-of-car compressive load.
Each carriage was four metres longer than a 5M2 car, increasing the passenger capacity, and the interior had air-conditioning installed, improving comfort.
It was found that, although the number of passengers and the length of the train increased, the power consumption and maintenance costs were less compared to the 5M2 class, and it was reported that the amount of energy consumed could be reduced by 28.4%.
[4][8] Experience from the 6M and 7M classes lead South African Railways to order an electric multiple unit model with thyristor chopper control from Nissho Iwai in 1985.
Since 2003, in order to improve reliability, reduce energy consumption, and extend the lifespan, refurbishment has been carried out to replace the control devices with variable-frequency drive using IGBT technology.