A look directly overhead into the ventilation shaft. It is obvious that the shaft has been closed using some regular sized objects- perhaps railway sleepers. Thousands of headlamps stare at us as we stand is a pool of sticky, smelly stuff…The yellow blob is made by the torch beam that helps the camera to focus in these totally dark situations.

We cannot guess why the railways chose to make this ventilation shaft in the exact center of this 177 meter long tunnel - other equally long tunnels in the same section do not have any ventilation facility. To add to the mystery, this tunnel is more or less straight, the others are curved and more likely to trap the smoke. A ventilation shaft would be easier to dig in the other tunnels which have lesser rock on the top - so why was this tunnel chosen for ventilation ?
We also could not guess why the railways chose to close this shaft and that too at the bottom end of the 33 meter depth rather than at the top.