Before and after vactrain

With Elon Musk's Hyperloop in the news, the vactrain concept has been closer to the fore of my mind. One angle I think it would be interesting to explore would be whether it would be possible and efficient to create a temporary partial vaccum in front of each train.

Such a design would require fans, in separate tubes, spaced along the length of the tube holding the train. As the train approaches, the fans would be used to reduce the air pressure in front of the train, by pumping the air behind the train.

The mechanism could potentially be used to power the train, as the pressure of the air behind the train would push it forward, particularly if there was relatively little air gap between the train and the tunnel wall.

Would it work?