Yesterday a train passed by with like 40 train cars and I was astonished by how these trains can even move with that much cargo behind it. How is this even possible?
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Trains use engines designed to provide massive torque while stationary.
Your car engine needs to spin fast to generate power, so it’s great at speed but terrible when stopped. You need a complex gearing system to generate any power at all when stationary, and messing up the transition just stalls the motor.
Trains use diesel-electric systems to turn the wheels with electric motors. These can generate enormous force even when the train isn’t moving at all, and that’s enough to get it rolling.
Old-timey steam engines used a similar idea – a steam engine is neither safe nor clean nor efficient, but it can generate tremendous power at a standstill with that steam pressure.
Once it’s moving, keeping it moving is trivial. The metal-on-metal wheel and rail design has very low friction and rolling resistance to a moving train will stay moving without much effort.
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