The electrification of the railway network meant that trains could run faster than before, but it also made it possible to operate longer and heavier trains. Consequently, train traffic could increase.

In some cases, the track beds had to be reinforced to accommodate this increase in weight and speed. Other common changes included straightening out overly tight curves and extending railway yards. Tunnels, bridges, and signals had to be modified to accommodate the overhead lines.

Even in the 1940s, each overhead line gantry was measured and custom-made individually. This work, like all excavation, concrete casting, and fastening, was done by hand.