Here is a view of the Jet Fan inside the 25C tunnel – we were actually standing below one of these while the 1007 Down Deccan Express came by. Our experience – the pin drop silence, the sudden gust of air rapidly exploding into a whirlwind, the thunder of the train rushing in, blinding headlamps, flashing windows, frozen faces, the unlit patch of the SLR followed the banshee howls of the three bankers – the sound recedes, the wind slows and finally dies. And yet, a metallic clattering continues very close – overhead ! We flash our torches on the roof and discover the first Jet Fan which was in a dark section of the tunnel. Maybe the Jet Fan system is not operational, because a working motor would make a different sound, but then it could work only when a train is passing, so one could not hear over the roar of the passing train. I feel that the Jet Fans are located before and after the ventilation shaft to force the upper tunnel air towards the vertical hole.