First Moscow electric train left the Yaroslavsky railway station on Moscow – Mytishchi route
The electrification of this suburban section came under discussion in 1924 due to the rapidly rising volumes of passenger traffic.
In September 1924, under the management of the Northern Railways, an electrification bureau was set up, which developed a draft design for the electrification of traffic on the sections between Moscow – Pushkino and Mytishchi – Shchelkovo. A direct current (DC) system with a rated voltage of 1,500 V was adopted as the power supply system that was then used in other areas with multiple unit traction.
The DC system was chosen because a single-phase current would require heavier and more expensive rail motor cars due to the need to fit them with transformers. In addition, DC traction motors, other things being equal, have a higher torque and are more suitable for starting compared to single-phase current motors. This is especially important for rail motor cars operating in suburban areas with a large number of stops, where high acceleration is required when starting off.
The voltage of 1,500 V was chosen because much less copper is required for the contact network compared to the 600-800 V system. At the same time, it became possible to create reliable electrical equipment for a rail motor car, which at that time could not be expected at a voltage of 3,000 V.
The electrification of the Moscow – Mytishchi section began in 1927. The trains were hauled by three-car sections consisting of a rail motor car and two trailers, one of which had a luggage compartment.
The experience of these first years operating the Moscow – Mytishchi section demonstrated convincingly the advantages of electric traction compared to steam and contributed to the expansion of the electric railway network. In addition to very considerable fuel savings, the introduction of rail motor-car traction made it possible to reduce significantly the locomotive and wagon fleet. As a result, by the early 1930s, 33 rail motor-car sections operated along this line, which in terms of carrying capacity replaced 43 train and shunting steam locomotives and about 400 suburban passenger carriages.