Severn Tunnel cancellations - trains unfit for tunnel use

[whole diary]

[grahame]

A series of these today

06:49 Worcester Shrub Hill to Cardiff Central due 09:23
06:49 Worcester Shrub Hill to Cardiff Central due 09:23 will be terminated at Bristol Parkway.
It will no longer call at Patchway, Severn Tunnel Junction, Newport (South Wales) and Cardiff Central.
This is due to a fault on this train.

09:50 Cardiff Central to Worcester Foregate Street due 12:17
09:50 Cardiff Central to Worcester Foregate Street due 12:17 will be started from Bristol Parkway.
It will no longer call at Cardiff Central, Newport (South Wales), Severn Tunnel Junction and Patchway.
This is due to a fault on this train.

So that will be a turbo with doors between the carriages not working ... the rather odd business that the Severn Tunnel is now regarded as an underwater railway and new train types are required to have doors that close between the carriages or they are considered unsafe.

Pity the people bussed up from Temple Meads to Parkway to then find that their onward train is cancelled. There will be some happy chappies today!

[martyjon]

So that will be a turbo with doors between the carriages not working ...

That's a new one on me.

Show me an HST^▸ (High Speed Train) with a door between carriages, the internal carriage doors on an HST gives access to the end vestibule but there is no door across the corridor connection. Even the Mk1 and Mk 2 coaches had a door at the corridor connection which was locked if it was the first or last carriage on a loco-hauled set with of course a blanking corridor panel placed on the outer ends of the set. Even then in the latter days of loco hauled stock I have travelled on services without these blanking panels, I know because I was able to look out of the small windows in the door to see the track disappearing into the distance although I never established if there was any way the door was secured on the outside. Could have been problematic if anyone mischievous enough was let loose on a loco hauled stock set with a BR1 key.

[bobm]

It is all to do with "grandfather rights".   Turbos are new to the route and therefore - despite much pressing from GWR^▸ (Great Western Railway) - do not have the same dispensation as HSTs^▸ (High Speed Train).

For the same reason I assume an IET^▸ (Intercity Express Train) wouldn't be allowed through if one of its internal doors developed a fault.

[CMRail]

So how come Class 700, 707s etc are allowed through tunnels?

[grahame]

So how come Class 700, 707s etc are allowed through tunnels?

I believe it's to do with the tunnel being an undersea tunnel.

[martyjon]

It is all to do with "grandfather rights".   Turbos are new to the route and therefore - despite much pressing from GWR^▸ (Great Western Railway) - do not have the same dispensation as HSTs^▸ (High Speed Train).
For the same reason I assume an IET^▸ (Intercity Express Train) wouldn't be allowed through if one of its internal doors developed a fault.

Does IEP^▸ (Intercity Express Program / Project.) diagrams have "connecting door examining time" to ensure all carriage connecting doors are operational before the services are despatched from either Bristol Parkway or Newport, I think not.

What a stupid restriction to be made particularly as Turbos are not new to the route. Many years ago Turbos were regular visitors to Cardiff for wheel turning on the Canton wheel lathe but then I suppose you could say that the restriction won't apply to an ECS^▸ (Empty Coaching Stock) working.

[SandTEngineer]

I wonder if anybody could make a 'Freedom of Information' request to see the output of the risk assessment that came up with that mitigation?  Trains aren't 'sealed units' are they?

[stuving]

I thought the reason for needing to close off gangways was so the train could be split there, in case only one part can be removed initially with passengers on board. The sectional appendix does have stuff about that, including the requirement that passengers may only be moved to the recoverable part via gangways, not outside. Which all sounds mildly sensible, until you apply it to turbos.

The SA I was looking at (June 2017) said class 165/6 were simply not allowed down that hole, in which case their approval must be part of the clearance programme for the cascade. But could you really split a 166 inside the tunnel? And why would you? Are trains of more than one unit banned -  that seems like a more realistic restriction?

[paul7575]

I thought the reason for needing to close off gangways was so the train could be split there, in case only one part can be removed initially with passengers on board. The sectional appendix does have stuff about that, including the requirement that passengers may only be moved to the recoverable part via gangways, not outside. Which all sounds mildly sensible, until you apply it to turbos.

The SA I was looking at (June 2017) said class 165/6 were simply not allowed down that hole, in which case their approval must be part of the clearance programme for the cascade. But could you really split a 166 inside the tunnel? And why would you? Are trains of more than one unit banned -  that seems like a more realistic restriction?

A discussion in wnxx forum a few months ago reckoned the restriction was to do with correct operation of the 165/166 interior gangway doors.  Fire resistance maybe if evacuating to an adjacent carriage?

Paul

[CMRail]

I thought the reason for needing to close off gangways was so the train could be split there, in case only one part can be removed initially with passengers on board. The sectional appendix does have stuff about that, including the requirement that passengers may only be moved to the recoverable part via gangways, not outside. Which all sounds mildly sensible, until you apply it to turbos.

The SA I was looking at (June 2017) said class 165/6 were simply not allowed down that hole, in which case their approval must be part of the clearance programme for the cascade. But could you really split a 166 inside the tunnel? And why would you? Are trains of more than one unit banned -  that seems like a more realistic restriction?

That’s why there’s short forms - they split in the severn tunnel 

[Trowres]

Is https://www.rssb.co.uk/rgs/standards/GIGN7619%20Iss%201.pdf relevant to this issue? - length of tunnel (>5km) seems to be the key determinant of more stringent regulations  being activated.

[Bmblbzzz]

This talk of a submarine railway – what has changed? There's always been a lot of water down there, has more been found? Something leaking?

[stuving]

This talk of a submarine railway – what has changed? There's always been a lot of water down there, has more been found? Something leaking?

I suspect submarinity may not be the issue, so much as the distance with no escape routes (which itself may be due to the lack of dry land above it). If the thinking behind the TSI has been adopted, whether the TSI has or not, that brings the idea of a minimum time that the train can run with a fire declared.

The idea (which may well have been present in the past less formally) is that it is almost always more dangerous to life to be on a train on fire stopped in a tunnel than to travel on it with the fire and then stop in the open. To make that work, it has to be possible to move away from a fire within the train, and retreat behind a fire partition with a long enough rated resistance. The TSI says they must be no more than 28 m apart, so at the gangways is an obvious place though not the only possibility.

The running time requirement for tunnels over 5 km in length (without safe evacuation areas) is 15 minutes, and that implies a lot of care routing the control cables and brake pipes and protecting them from the main fire sources - the engines and their auxiliaries. Multiple separate engines are obviously good for this, but I wonder how well turbos score on these other factors. The Severn Tunnel, by the way, is 7 km long.

In any case, once I'd found out where the current Sectional Appendix is hiding, it says class 165/6 are still not allowed through the Severn Tunnel at all!

[phile]

This talk of a submarine railway – what has changed? There's always been a lot of water down there, has more been found? Something leaking?

I suspect submarinity may not be the issue, so much as the distance with no escape routes (which itself may be due to the lack of dry land above it). If the thinking behind the TSI has been adopted, whether the TSI has or not, that brings the idea of a minimum time that the train can run with a fire declared.

The idea (which may well have been present in the past less formally) is that it is almost always more dangerous to life to be on a train on fire stopped in a tunnel than to travel on it with the fire and then stop in the open. To make that work, it has to be possible to move away from a fire within the train, and retreat behind a fire partition with a long enough rated resistance. The TSI says they must be no more than 28 m apart, so at the gangways is an obvious place though not the only possibility.

The running time requirement for tunnels over 5 km in length (without safe evacuation areas) is 15 minutes, and that implies a lot of care routing the control cables and brake pipes and protecting them from the main fire sources - the engines and their auxiliaries. Multiple separate engines are obviously good for this, but I wonder how well turbos score on these other factors. The Severn Tunnel, by the way, is 7 km long.

In any case, once I'd found out where the current Sectional Appendix is hiding, it says class 165/6 are still not allowed through the Severn Tunnel at all!

The ones that have been running through the tunnel day in and day out for a year now.    One of the banned ones recently escaped through and when it was realised, it was on it's way back. !!!

[Bmblbzzz]

Okay. And yet after the 1996 Channel Tunnel fire, their policy changed from having the train drive through the tunnel, to stopping where it was and evacuating. But then they have the service tunnel for this.