Edwin_m

If the engine was running that would provide air on the loco(s), but if the train air brakes were applied the pressure in the single train pipe would be low. Hence there would be no air to recharge the wagon brake reservoirs and the wagon brakes would leak off regardless of what the loco was doing. If all was in order the locos would provide enough air braking to hold the train, but this would be lost some time after the engine shut down. But surely it's one of the first rules of railway operating never to leave a train unattended on the air brake? There are all sorts of reasons why it might leak off if not monitored by the crew. The train should have been secured by means of loco parking brakes and/or wagon hand brakes.

At the other end of the tunnel they were headless as well.

My grandfather apparently ran a garage on Ducie Street* until he was called up for WW2 - I can't see any sign of it on this thread so far but would be interested if anyone has any info/pictures. *Family history could possibly be confusing with Great Ducie Street, round the back of Victoria.

The summary linked by 47708 does refer to speeding up Aberdeen trains by diverting some onto this route from via Fife, which would potentially reduce usage of the Tay Bridge. However I can't see that an Edinburgh-Aberdeen train would be noticeably quicker by this route, as it doesn't look much shorter. There could also be capacity issues on the single line out of Perth towards Dundee. Another concern would be capacity out of Edinburgh. Trains via all routes would still have to use the double track via the Forth Bridge, so there is a risk that diverting some trains via Glenfarg would reduce the fast service on the existing route.

There will be some trains between Manchester/Leeds and Birmingham which won't touch the busiest part of HS2, which is between London and the junction where it splits for central Birmingham and everywhere else. Despite this the sections north of Birmingham will be less intensively used than the section further south. There are various ideas floating around about using this capacity for other services, but they are not part of the current plans for HS2.

It does say somewhere that the terminal capacity is based on a turnaround of 30min, which squares with Mike's previous calculation and 11 platforms. Not considered, but perhaps worth thinking about, is that a Birmingham journey under an hour may be able to get away with a shorter turnaround (though the Scottish ones could be longer).

The issue at Paddington would be accommodating the 400m trains that will run on HS2 (2 coupled sets). This is the European standard for high speed routes and building for anything shorter would immediately reduce the passenger capacity in proportion. From Praed Street to the far end of the trainshed is only about 200m, so a high speed terminus here would involve widening and remodelling the throat (which may be too tight a curve for platforms in any case) or extending through the Lawn and under streets and hotels with the buffer stops underground somewhere near Sussex Gardens. The low-level station at Euston would also need 400m platforms but this probably just means they would be accessible from Euston at one end and St Pancras at the other. Shorter journey times will reduce the train fleet size, with savings in staffing and depot size, because a faster train can do more journeys in a day. They do of course increase energy costs. The alignment is mostly designed for 400km/h but reduces to lower speeds in various places where environmental constraints mean curves are too tight for this speed. This suggests that if there were other alignment constraints that would be more easily overcome at a lower top speed then the speed on that section would also have been reduced. The quoted journey times are based on an Alstom AGV with maximum speed of 360km/h but assumed to run at only 330km/h when on time (where the infrastructure permits) to give some margin for recovery from delays. As to 9min time saving, this is getting on for 20% of the London-Birmingham HS2 time. Experience with routes such as the ECML suggests that a 10% reduction in journey time on a long distance train will lead to a 9% increase in demand. There may be an even greater benefit if journeys can be brought within the threshold of 3-4 hours where rail becomes competitive with air on journey time. This doesn't apply to Manchester and Leeds, which have virtually no London or Birmingham flights these days, but could be important for Scotland. So the consequences for demand, revenue and the benefits of reducing car and air journeys do depend quite strongly on maximum speed. Nobody can say now with any certainty what the optimal speed will be in ten or 20 years time. There is particular uncertainty on energy costs, which will affect not only the cost of running the service but also the attractiveness of other competing modes where energy forms a greater proportion of the total cost. There would be no reason not to use a lower speed if that proved to be the best balance between demand, operating cost and environmental issues, but if the route was designed for lower speeds it would be almost impossible to upgrade later.

The latest proposal for Euston has 11 high-speed and 13 conventional platforms. There are various documents regarding capacity, this one for example shows a minmum headway a shade over 2min and a capacity of 18 trains per hour. This is based on a normal maximum speed of 330km/h with 360km/h being used to recover from delays. The published end-to-end times are based on the same maximum speeds.

Martyn has posted the reason why a stopping train would cost two paths even if its top speed was the same as the non-stopping trains and the station had long accelerating/decelerating tracks with junction points that could be taken on the curve at that top speed. It isn't a problem at OOC because every train will stop, nor at Birmingham International because there is parallel running from the platforms into the branch junction, but it would be a problem for any station where neither of these apply. Strictly speaking you could have fewer than alternate trains calling but each train calling would have to wait there until just before the next one arrived. It would be great if a Calvert interchange could be made to work, though as I suggested above it would be more for journeys to/from the North than London, but I can't see it happening.

That wouldn't work either. The 395 equivalent would be significantly slower than the longer-distance trains, so would take up several high speed paths on the busiest part of the network. This is in addition to the issue I noted above, where every train stopping at a Bucks station uses up two through paths. Even if it had a frequent train service the benefits for Bucks of a station are themselves a bit limited, at least in respect of travel to London. Except for people who live very close to wherever any station would be, the extra time to access a less convenient station would outweigh the time saving on the relatively short journey to Euston.

You are in esteemed company in thinking this - the Roskill Commission in 1968 favoured a site about ten miles to the east. Google for "Cublington Airport" to find out what happened next...

That's only so if you stop every train.

in practice a station in the Chilterns would have a signficant effect on route capacity. If all trains were proposed to stop then there could be two or even more parallel platforms in each direction so that as a train was leaving a platform another was arriving in a different platform. This would have no capacity impact but all trains would have to stop, which would be excessive for the demand on offer and increase the journey time for everyone else. The Japanese option is to have long loops serving the platforms and to have one or more non-stop trains overtaking a stopping train. However a stopping train would require at least two paths, one ahead the non-stopping train(s) and another behind them. This may be less of a problem in Japan because there are several such stations so each stopping path is probably used by a different train on a different part of the line, but with only one new station this wouldn't be possible on HS2 except perhaps between OOC and London or between the two Birmingham stations. The line between OOC and the Birmingham branch junction is likely to be the busiest part of the eventual HS2 network so the result of a station in the Chilterns would be the loss of one train to/from further north for every train that stops. In order to have more stations, HS2 would really need to run through areas of greater population, multiplying the disruption and objections and also abstracting passengers from existing rail routes that serve these areas rather than the intended result bringing in more passengers onto rail from car and (when extended further north) also from air.

If an area is controlled by, say, five signalling centres instead of one, then any of the above can go wrong at any of the five and because there are five of everything the overall rate of incidents will be about five times higher (assuming the centres are similarly equipped apart from size). I would argue that loss of any one of the five would probably screw up the network just as effectively as loss of one centre that covers the whole area.

Presumably any European service to Heathrow would use part of the HS2 Heathrow loop for which provision is being made in the Phase 1 design. However to my mind the problem previously identified still exists, that Heathrow isn't a single place and if you need a shuttle to get to the correct terminal then you might as well interchange at Old Oak and use Crossrail (or Heathrow Express) as the shuttle. All of this assumes of course that Heathrow remains in the same place with largely the same role.

I was referring to the baggage checks, which are purely to do with alleged security of the Tunnel not related to immigration. The UK border checks wouldn't prevent people using a Tunnel train in either direction between UK stations. I don't think France/Belgium imposes similar checks in the other direction but if they do (perhaps because the UK has left the EU?) it would again make it difficult for UK passengers to use the trains between UK stations.

As shown by recent events, the terrorists can create mayhem without resort to bombing trains or anything remotely hi-tech. Because of the structure and pressurisation of an airliner and the fact that it falls out of the sky if seriously damaged, it is possible to kill a lot of people by bombing a plane, not to mention the 9/11 scenario. Hence access to aircraft is quite rightly strictly controlled. However a train is different and while a bomb in the Channel Tunnel would be serious, it would not be in remotely the same league as a bomb on a 747 (as 7/7 and the Madrid bombings demonstrated - and note that both were soft targets rather than high-profile rail operations). In fact it is quite possible more fatalities would be caused by detonating a bomb in the security queue, and more damage to the Tunnel by igniting a HGV. This has already happened twice without any malice aforethought, but did show that the Tunnel itself can be got back up and running quite quickly albeit with single line running in one section. Hence why I consider the security checks for the Eurostar are grossly disproportionate to the risks it poses and seriously damaging to the market for international rail travel beyond London. But I don't believe it will change because the "security ratchet"+ is in operation and the zombie factor* comes into play. +once security has been increased it is almost impossible to reduce it again *the fact that there have been no successful zombie attacks proves that our expensive and annoying anti-zombie precautions are worthwhile.

Euston Cross would be north of the British Library. It is proposed to have a cut-and-cover concourse under a road (Brill place I presume) with the actual platforms in bored tunnels which would probably be deeper. From the sketches in Modern Railways they seem to have taken account of the numerous tunnels in the area. HS2 classic-compatible services would terminate at the existing Euston station which would change relatively little, and taking them off HS2 in the Queens Park area would allow regional domestic services to replace them from here onwards. "Captive" high speed stock would pick up and drop off at Euston before working through to a turnback and servicing facility somewhere on HS1. I think the "regional" version of Crossrail 2 would do something similar, with a combined station accessed from Euston at one end and KX/SP at the other. Hopefully the two proposals are also compatible with each other. As Martyn suggests, how international services fit into this proposal depends on the future security rules. To me running them via Euston Cross only makes sense if we adopt the precedent of every other railway in the world and allow them to carry both domestic and international services without additional security checks. In that case they could be simple extensions of trains coming in from further north - otherwise they would have to run as additional services which would mean the section around Old Oak limits the capacity of the national high speed network. Either way there is some chance of terminating capacity being freed up at St Pancras, which could be used for extra MML platforms or perhaps something like a shuttle to wherever the main airport is by then.

The biggest problem with converting to European gauge is likely to be the platforms. They need to be set further back and so can't be used by UK gauge trains as the gap is too big. So you have to factor in some fairly horrendous logistics including significant suspension of service during the conversion and/or through services having to be split for long periods with passengers changing trains en route.

Oddly enough I had a query yesterday from a colleague (with no particular rail background) who was doing a traffic assessment for a new housing development that would be accessed via an existing level crossing. He wanted to know what the rules are on whether this would require a crossing upgrade. So it does get considered. some of the time at least.

I read of some being installed (Waterloo approaches???) which were a stencil with a plain white/red circle immediately behind, so they looked like a road sign but were still to some extent legible when covered with dirt, snow or graffiti. Or did I imagine this?

No problem with speeding up, within reason, as long as people can and do stop at the lights if they start flashing (and obviously also take account of any other road-related hazards). In fact in some ways slowing down is more dangerous as you pass over the crossing more slowly and are at greater risk of stalling on it.

"Stop look and listen" for a road vehicle arguably makes things more dangerous, because of the risk of starting off in the wrong gear and stalling on the crossing, and also the false sense of security if the driver doesn't see or hear anything.

If the site is suitable then bridge replacement may be viable on a purely financial case leaving aside the safety benefits. A bridge probably costs more than replacing/upgrading a level crossing but it lasts a lot longer and does not cause operational incidents. The difficulty is often that there is not space for a bridge or local landowners/residents object to one.

Yes I agree that rail accident statistics are a minefield, particularly as the events in question are so rare as not to be statistically significant and the human brain is not good at dealing with very unlikely but very severe risks. Better minds than I have worked to produce things like the RSSB risk model which attempts to get round this type of problem and presents the best estimate of the risk from a range of sources based on comprehensive data over quite a long period of time.