The new technical creation, the underground, was regarded as a pioneer in many aspects when it was opened. The whole railroad and vehicle fleet were ahead of their time. This was the first time Siemens had applied its electric traction for any means of urban public transportation. Traffic was controlled by a motor buggy, electricity was provided by generators powered by steam engines. The railway got its required 350 V of working voltage via steam engines and generators from the power plant on Akácfa Street. Because of the low height of the tunnel, a special electricity collector was applied on the cars.