QUOTE (Bear 1923 @ 14 Nov 2019, 08:23)
<{POST_SNAPBACK}>Actually - thinking about it - I don't recall anywhere where I have seen surface evidence of a drain or drains in a tunnel. Given how wet they often are there should/must be something...
From what I have seen, it really varies, depending on the ground through which a tunnel passes. All tunnels I have seen have had some form of drainage, usually a channel on one or both sides or in the case of double track tunnels, a channel down the middle, usually covered. Wherever the channel is located, there will be periodic drain covers - I recall seeing these through Sharpthorn tunnel prior to the Bluebell reopening.
Prior to major works to reinstate the failed drainage system, the southern end of Sharpthorn tunnel was an absolute swamp with the water running out of the tunnel like a river.
Drainage (or lack of) can result in the structural failure of a tunnel, particularly if water gets behind the lining and support - there have been a fair few examples of collapses because of this. There's a website (Forgotten Relics or tunnels?) which has numerous photos of tunnels. Collapse seems to have been a common problem in some parts of the country where collapsed tunnels were basically burried and sealed as too dangerous to repair.
My experience of railway tunnels is that they are the darkest, coldest, spookiest places you can be. The sort of place where your torch 'fights' against darkness! I found looking up smoke stacks to be the most spooky thing to do!
I wouldn't necessarily say they are filthy, dirty places - I have walked through a fair few. That really depends on where they are, what went through them or what goes through them now and/or whether the trains were under high throttle.
QUOTE (Bear 1923 @ 14 Nov 2019, 08:23)
<{POST_SNAPBACK}>In winter ice is a problem in tunnels. It's hardly ever mentioned. However, it used to be a regular Pway job to go in with stout poles to smash ice off tunnel roofs. H&S would freak out about the risk now. "Back then", with very poor lighting (poor torches or oil lamps) it was hard to see what ice there was and how big it was - consequently whacking one bit the men never knew just how much would come down - or where. They needed to be able to leap out of the way fast. In my own time I've also know ice form a slab across the tunnel floor. In Box Hill Tunnel an 8 SUB (2x4) smashed off all of its traction shoes against a massive slab of ice right across the tunnel floor. The good thing was they were the old really heavy units - I doubt that a modern unit (possibly even an EPB) would have stayed on the track. The SUBs simply smashed their way through and then trundled to a stop.
I recall that ice used to be be a major problem in Haywards Heath tunnel. Water would ingress via the two smoke stacks and would create huge ice formations which would result in tunnel closure while the ice was cleared. I believe they also had the sheet problem you described too. The smoke stacks were re-sealed to prevent water ingress and I believe that there is little/no problem today.
