[bluGill]

The trolly lines removed were mostly electric. Steam trains did come first but everyone was into electric trains in the 1930s.

for freight there were different considerations and electric didn't have the needed power.

[fuzzzerd]

Ironic that the diesel that replaced steam and pure electric is actually diesel electric.

[bluGill]

Not really. The problem with electric (in 1930) is the low voltage (relatively low - still 600-1000 volts!) couldn't handle the needed watts for diesel.

Steam was more fuel efficient than diesel when it was replaced. But a diesel engine could start in less than a few hours, and needed one less person on the crew so it was cheaper overall.