Posted By Graham Bullough The wagons which carry vehicles through the Channel Tunnel have mesh-like superstructures. Thus, if any fire occurs on a vehicle being carried, the movement of the train within the tunnel effectively forces air to the fire. If the wagons had sealed superstructures, this fanning effect would be avoided. In addition, such wagons could be fitted with smoke and heat detectors linked to systems to enable the interior of a wagon to be flooded with carbon dioxide to extinguish the fire. I'm no expert on fire matters but surely the above relates to one of the 3 basic requisites for supporting combustion, namely the provision of air or more accurately oxygen. Carbon dioxide flooding simply counters this provision. Presumably a safety case was considered for the tunnel before it came into operation: Does anyone know if this included the foreseeability of fires occurring on trains going through it? Even if it didn't, surely the consequences of the first major fire in the late 1990s (tunnel closed for 6 months or so and costing millions to repair, plus the revenue lost during closure) ought to have prompted a re-think and change to the vehicle carrying wagons. Can anyone provide any informed advice on this aspect? Now that another fire has occurred, does anyone think there is any chance of a re-think about fire detection and control? I've had a skim for information about this on the internet, but it's like wrestling with fog because nearly all the hits are about the problems experienced by intending tunnel users because of the latest fire. While on the subject of carbon dioxide extinguishing systems, years ago I visited a number of normally unmanned underground power stations in the Scottish Highlands which had such systems. The employees who visited to check or otherwise work in them from time to time said that they were always careful to ensure that the systems were locked off before they went inside. Perhaps the Channel Tunnel wagons don't have such systems because their activation would kill any stowaways who had got onto the lorries within them! A final thought: Be thankful that the Channel Tunnel comprises a rail tunnel. Mrs Thatcher as Prime Minister was apparently very keen for it to be built as a road tunnel. Just imagine the number of crashes and associated carnage, damage, loss and tunnel closures which would have occurred by now if she had got her way!

Posted By John Richards The original design had fully enclosed freight transport wagons. They were too heavy to cope with 44 tonne trucks so were redesigned to be lower and lighter, and hence mesh sides. In all the designs the problems were always going to be getting people out fast when, not if, a fire/explosion occurred. In reality, the mesh design has probably reduced the risk of explosion. There is a large amount of design fact out there. http://en.wikipedia.org/wiki/Channel_Tunnel

Posted By Colin Reeves There was a massive concern from local unions and politicians when the mesh trucks were first proposed. This based on two points, one that enclosed wagons would be safer, also the playing field was not level, ferries have to have effective fire fighting systems, why should the tunnel trains not have to have effective fire fighting systems - was this based on economics. Of course, this could NOT have been the reason, could it .......? Wording now is "we told you so .." Colin

Posted By Tabs Nervous of not having looked it up, http://www.pacts.org.uk/statistics.php?id=3 tells me that fatality per billion passenger kilometres are: Car = 3 Rail = 0.1

Posted By Mitch She never lost an election but was never voted in by the majority of the country!

Posted By Crim I've never been through the channel tunnel, don't go that way very often and have used the boat up to now. One point re CO2 - people stay in their vehicle while on the train so total flooding would just kill everyone off. Put that in your statistical pipe and smoke it!

Posted By Fornhelper Sorry Graham....the name just hits a raw nerve with me !!! :-) FH

Posted By Colin Reeves Crim One point, unlike the passenger shuttles, the lorry drivers move out of their cabs to separate carriages so, apart from the odd illegal immigrant, nobody would be affected if the wagons were flooded with CO2. Colin

Posted By Tabs RobT I agree then, fly planes through tunnels. Their rate is 0.01 Good call.

Posted By Pete48 Graham, in fact both the French and Englsih governments wanted road tunnels along with a huge slice of the European road haulage lobby. Wasnt the political respnse that Eurotunnel were required to present a feasibility study into a second tunnel that included road with segregated freight and car traffic? I seem to recall that finally hit the buffers (!) in 1999. As for your question, you may have a point but I am uneasy about looking at just one aspect. How can one assess the overall impact of such a design change without having a holistic view of the system arrangements. Introducing a different fire suppression system, that of itself introduces another hazard into a tunnel, cannot be done on such a simple analysis can it? Is the safety case or risk/cost analysis study for the freight wagons in the public domain? If so can someone post the link for us? If not, we risk being accused of idle speculation methinks.

Posted By Bob Youel I was involved in a number of safety case studies for the tunel and it was easily forecast that such fires were likely - all foreseeable areas were taken into account incluse of lorry weight, carbon flooding etc - we also provided the answers It is interesting that in the safety cases I was involved in [rigs, nuclear power and similar areas etc], the one, in my opinion, with the most certain maths present was also the one where the maths had the smallest impact on some final decisions i.e. the tunnel Mrs T was in many ways brilliant. Her husband was also a major haulier and represented the organisation so it does not take a maths specialist to put 2 and 2 together! Additionally the share holders may not be affected by such fires because the bills are picked up by me, the rate and tax payer, and the profits are picked up by them as per may other such schemes - whilst I am not to sure of the exact maths etc involved here I would bet that my thoughts are basicially correct!

Posted By ChrisM "There is no statistical evidence that I know of to suggest it is more dangerous for cars in tunnels than trains." Errr...well there is.

Posted By Andy Petrie Cars are more dangerous than trains, fact. It makes no difference whether they are in tunnels, on the surface or on a flyover. If you compare road tunnels to tunnels with electric trains, then they are much more dangerous due to the high levels of combustible fuel. Even with the channel tunnel carrying vehicles, the likelihood of a collision (and hence fire) is much less. The consequences are likely to be less as it is possible for the train to keep going until it is out of the tunnel.

Posted By Tabs Dear Moderator, I can't help but smile an ironic smile ... so one poster can sing the praises of Mrs T and the rest have to hum. No complaint. Just a smile :-/ The irony comes from what she stood for and how she achieved it. To the original poster, Graham, I would say the lesson to learn is that commerce will always compromise safety when things are done for profit... it is just a question of "to what degree?" So much debt has been written off on this project over the years, that it is unlikely that a change to a safer system will ever be considered. I've never used the tunnel - doubt I will do any maths before I do though ... I will probably decide on cost and convenience of times.

Posted By Rob T Hey Tabs, Please do remember cost/benefit analysis - commerce does have an acceptable face within safety but with provisos. Profit must come into play otherwise no companies could exist. That's what we are here for in many cases - to assess what an acceptable risk is. It's when we say that finance has no place in safety that we get (quite rightly) slaughtered in the press. Remember the HSE have often said that they are not risk averse (in their case debateable) and that's the way the world should be.

Posted By LMR Am I really as old as Methusala to recall the last fire in the tunnel (it was after Julias Ceasar - so not that long ago) when it was said at the time that the mesh design of the carriages had in fact been proven to save lives? There were areas where lorry drivers could go for rest breaks etc whilst the train was in the tunnel and that design too helped to save lives? It is only the freight trains on this style of carriage - not passengers or cars! and also on a large number of these consignments it is only the container part of the wagon that is on the train in a mesh sided container; they get collected or delivered at each end by the tractor unit (lorry cab!). Since the original fire there have been increased safety zones put in place in the main tunnels leading to the 'service' tunnel between the two; the seals to that area have been improved and air is pushed through the service tunnel for increased safety. The extremes of heat in the tunnel caused by the fires itself speaks testaments to the design and safety features working.

Posted By Arran Linton - Smith Just to try and close this discussion, I worked on the Class 92 project and at the time of the development the mesh canopy on these wagons was developed because of other risks. It is very easy to get involved in speculation after the event, however as there are many complex fire engineering (and other risks) relating to the use of this infrastructure, I would prefer to wait for the outcome of the enquiry.

Posted By John Richards They thought about it at length LAST fire. At GREAT length. Every PRO also had an ANTI. Driving the train out also depends upon whether it will actually MOVE. Fires tend to make metal parts expand and distort. They also tend to burn through power cables.

Posted By TBC I travel through the 'Chunnel' regularly and the passengers do stay in or with their cars, but if a fire occurs in their carriage - they are to move out to the next carriage with the train continuing. I don't know if it has a flooding system for the effected carriage, but Co2 extinguishers are available. Does anyone know if it floods? I have not seen any mention of it. Has anyone got problems with spell checker on this site or is it my PC setup?

Posted By John Richards From all the [various] intermediate reports it would seem the train stopped extremely rapidly, throwing people onto the floor. One person stated that the loading supports were down on one carriage. The smoke inhalation is being put down to people panicking and leaving the units before the smoke clearance ventilation was activated. All this supposes that the power system had not been damaged by the fire.