# Why do all high-speed trains run on electric track (as opposed to normal track with diesel-electric trains)?

AFAIK, all high speed trains (200+ kmh) run on electric track.

Why is this? Is there something about a diesel-electric engine that makes high-speed trains more difficult?

Here's some other data, and correct me if I'm wrong:

Electric track is high-maintenance. Using a pantograph to pick up power from overhead wires is also non-trivial at speeds of 200 or 300 kmh. The electric system is much more prone to failure in bad weather (storms, snow/ice, etc.).

I've often heard the claim that electrified rail is more energy-efficient than a diesel-electric. However, I've never seen numbers showing exactly how much more efficient it is compared to diesel-electric. Maybe someone knows a source on that.

• Not quite true : en.wikipedia.org/wiki/British_Rail_Class_43_%28HST%29 which does explain some of teh constraints. Low axle weight is probably easier in a locomotive with the prime mover somewhere else. Oct 22 '16 at 10:20
• @BrianDrummond Thanks I will read about that engine. Low axle weight is probably easier in a locomotive with the prime mover somewhere else. Yes, but only for the engine car(s). In modern diesel-electrics, the electric power is sent to the wheels of many or all of the car bogeys. In other words, each car has its own electric motors driving its own wheels. This is true in a modern diesel-electric and a fully electric system. So the cargo cars have the same weight. Oct 22 '16 at 23:26