The Distant signal of Khandala inside the 25C. Note the store inside the tunnel with sleepers and other track material – such caches are available regularly through the tunnel. They also serve as convenient refuges when a train comes along.
In the ear wrenching silence of the 25C, one does not hear the train first – the dank, stagnant air starts wafting suddenly, the rapidly increasing breeze is your initial warning. Then you hear a queer boxing, roaring sound, and then the horn – by this time, you have to find the nearest refuge, unless you would want to stand in gutter full of cold water, slime and what else ?
The passage of a train outside the tunnel, on the other lines can also be heard as a brief but loud roar that starts all too suddenly.