Reply #6: NSTAAFL

[Ready4Change]

No Such Thing As A Free Lunch.

In short, any energy you harvest has to come from somewhere. In this case, it comes from the train. The most significant amount you could harvest would probably be from sideways air motion, rather than motion along the tracks. Air is moved sideways as the train approaches, then moves sideways again to fill in the vacuum gap where the train was. I suppose this could be collected with bidirectional turbines, creating an alternating current.

But if you significantly harvest this you will have the effect of increasing the pressure ahead of the train, and increasing the vacuum behind, resulting in increased drag and increased load/fuel burn on the train. You would in effect be converting the trains engine into an extremely inefficient generator.

There is a very small amount of energy in the air flow along the tracks after the train passes. But any energy gained from that would be outweighed by the cost of the equipment needed to recover it.