Severn Tunnel safety

Discussion in 'UK Railway Discussion' started by island, 7 May 2015.

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  1. island

    island Established Member

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    Is it true that a HST with a power car missing or inoperative can't go into the Severn Tunnel in case it can't get back out?
     
  2. Searle

    Searle Established Member

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    Would make sense, it seems to struggle out of the tunnel with both engines working :P
     
  3. louis97

    louis97 Established Member

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    Can't see anything in the sectional appendix prohibiting it, and I am fairly certain I've read before of HSTs operating Swansea-Paddington services with only one engine. As you won't ever need to actually stop within the tunnel, and you'll be going 75mph through it anyway can't see any reason a train won't get out if operating without any other faults. (Lights are present half way through the tunnel to advise when to apply power, freight trains use them).
     
  4. Envoy

    Envoy Member

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    I boarded a south Wales bound HST at Paddington. We were informed on departure that only one of the locomotives was working and that the train would be slower than normal. The acceleration was markedly slower than normal and it arrived in Cardiff 30 minutes late. So, yes, HST's with only one engine working can go through the Severn Tunnel.
     
  5. 455driver

    455driver Veteran Member

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    A HST on one engine must have a clear run through the tunnel before being allowed in, that's about it really.
     
  6. Flamingo

    Flamingo Established Member

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    Never heard of it. The only restrictions I am aware of with the Severn Tunnel is that a passenger train and a freight with dangerous goods / a steam train can't be in it at the same time.

    I've worked several HST's on one power car through the tunnel.
     
    Last edited: 8 May 2015
  7. Jonny

    Jonny Established Member

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    I thought it was a single block anyway. Given that, why would it make any difference?
     
    Last edited: 8 May 2015
  8. 455driver

    455driver Veteran Member

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    There are signals in the tunnel, I don't go down there but I think its in 3 sections.
     
  9. louis97

    louis97 Established Member

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    The only signals in the tunnel are repeaters for the signals at each end. The tunnel itself is just one section. Both lines through it are bi-directional also.

    There are also red lights that are illuminated in the event of an emergency and if lit you are to stop.
     
  10. 455driver

    455driver Veteran Member

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    Thanks, serves me right for only looking quickly at it.
     
    Last edited: 8 May 2015
  11. Mugby

    Mugby Established Member

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    I do believe though, that if all pumps failed at the same time, the tunnel would be flooded in less than five minutes!
     
  12. Flamingo

    Flamingo Established Member

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    The reason there are several, including back-up pumps.
     
  13. edwin_m

    edwin_m Veteran Member

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    Does that mean a steam train can only go through if it is not carrying passengers?
     
  14. Flamingo

    Flamingo Established Member

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    No, sorry, I wasn't clear. A steam train and a diesel passenger train usually won't be allowed in together. I'm not sure about a steam and freight at the same time, but I doubt it.
     
  15. sbt

    sbt Member

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  16. PeterY

    PeterY Member

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    Are the repeaters the standard type Banner Repeaters used elsewhere on the network?
     
  17. louis97

    louis97 Established Member

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    No, they are actual repeater signals, the signals before entry are 2 aspect therefore a green/yellow repeater signal are required. A banner repeater is generally used for when a signal is not visible till you are at it, although they can also be used to extend the length of time you know the next signals aspect. An example of the latter is on the Midland Mainline in relation to the line speed increases and also between Bath Spa and Bristol in the Keynsham area where a new signal was added - requiring more notice of signal aspects to allow adequate braking distance.
     
  18. gwr4090

    gwr4090 Member

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    The Sectional Appendix doesn't mention anything about restrictions involving steam trains, just freight trains carrying dangerous goods.
     
  19. Taunton

    Taunton Established Member

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    I believe the gradients down to the bottom of the tunnel are not that steep, only 1 in 90/100, so not really an issue if only on one power car. The river is not actually that deep at this point.

    I'm surprised that it's now a single block section through there, as intermediate colour light signals were installed in there back in GWR days; must have been removed at some time. The rails in there only lasting a few years was also a feature of the tunnel back in steam loco days.

    I always felt it unfortunate that when the second, most recent, road bridge was built, which closely parallels the rail tunnel, that advantage was not taken to build a combined rail/road bridge, and finish with this maintenance and operational liability.
     
  20. Flamingo

    Flamingo Established Member

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    The steam train thing is something I was told, as the fumes cause everyone on the diesel train to panic as they think the train is on fire. I've been in a train that went through behind a chuff-chuff and it was "interesting"!
     
  21. headshot119

    headshot119 Established Member

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    I'd say there are a lot less banner repeaters on the network than there are repeater signals.
     
  22. Johnnie2Sheds

    Johnnie2Sheds Member

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    Interesting. I do remember as a teenager being on a train hauled by D1059 Western Empire (XX:XX Paddington Cardiff) in about 1975, rolling into the tunnel and being brought to a near stand at what I assumed to be the bottom of the tunnel. I could clearly see ladders down to what I thought would be the sump or pumps. We were doing walking pace when the signal cleared. I can still hear it. :)
     
  23. D1009

    D1009 Established Member

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    Isn't that the case with any tunnel, though?
     
  24. Taunton

    Taunton Established Member

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    Extraordinary. I can (just) recall going through in steam days. A lot of coal, including all that Welsh steam coal for the rest of the Western Region loco depots, came through the tunnel, double-headed, commonly by a 2-8-0 assisted by one of the 2-6-2T tanks specially kept at Severn Tunnel Junction for the purpose. There would be a continuous parade of these in between quite frequent passenger services. Despite all the fans the tunnel atmosphere never cleared because of the intense service, all the regular passengers knew it and would slam the sliding ventilators shut as you entered. There was a most distinctive smell about the place.

    Having said that, there were much worse tunnels on the system. The Severn is at least double track, with air space alongside. Being on a double-header on the S&D going out of Bath through Combe Down tunnel, single track, 1 in 50 up, no ventilation, and very tight with the chimney blasting at the tunnel roof just inches above, was way worse back in the train, what it was like on the second loco doesn't bear thinking about. If you got a slip you might not be certain which way the train was going (the crew would put a stick out against the tunnel wall to test).
     
  25. Flamingo

    Flamingo Established Member

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    I suppose so, but the longer the tunnel the worse it is.
     
  26. Carlisle

    Carlisle Established Member

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    Maybe these changes you describe to the signalling block sections were made in the aftermath of the 1991 Severn tunnel accident
     
    Last edited: 12 May 2015
  27. edwin_m

    edwin_m Veteran Member

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    Combe Down tunnel was fatal on at least one occasion, even without the "benefit" of double heading.

    http://www.railwaysarchive.co.uk/docsummary.php?docID=1999
    --- old post above --- --- new post below ---
    When a Severn barrage was being talked about, it was proposed to run a railway across it.
     
  28. Railsigns

    Railsigns Established Member

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    The GWR installed intermediate block signals inside the tunnel in 1941 and removed them in 1947.
     
  29. Flamingo

    Flamingo Established Member

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    it was probably going to be slower than the tunnel, by the time the train driver stopped at the toll booth, got out his money, got his change and receipt, waited for the barrier to raise and pulled off again there was no speed advantage... :lol:
     
  30. PeterY

    PeterY Member

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    LOL. Only want to cross the bridge not buy it. :D
     
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