I have also noticed that empty freight trains weigh the same as loaded freight trains which is daft and unrealistic. In hilly terrain were the mine or forest is located higher than the processing plant it should be possible to use smaller locomotives, as gravity would assist the descending (loaded) trains leaving the loco to haul the empty (lighter) trains back up the hill.
I also agree that electrification should be very expensive to install initially, then the electric trains should have significantly lower purchase price, running costs and a longer life.