Spartacus
Established Member
- Joined
- 25 Aug 2009
- Messages
- 2,979
Jeez, this chestnut's so old a starving squirrel wouldn't touch it.
If you want to challenge (un)loadong times, go to Paris Gare du Nord, in particular the RER platforms. It can take a good 5 mins to unload and reload a full double-decker train, which must severely limit capacity. Now compare that to the wide, spacious, quick loading 700s that run on Thameslink!not really... a bus has {usually} one door... meaning 70 people per door... an 8 car train will have 2 doors per carriage... meaning 16 doors... 1000 passengers / 16 doors = 62.5 passengers per door.
you mean the wide spacious quick loading 700s that everyone seems to hate? of course the natural question is how wide are the doors on a 700 compared to those on a DD RER train?If you want to challenge (un)loadong times, go to Paris Gare du Nord, in particular the RER platforms. It can take a good 5 mins to unload and reload a full double-decker train, which must severely limit capacity. Now compare that to the wide, spacious, quick loading 700s that run on Thameslink!
you mean the wide spacious quick loading 700s that everyone seems to hate? of course the natural question is how wide are the doors on a 700 compared to those on a DD RER train?
People hate 700s because they have horrible seats and they aren’t 319s. I don’t much like them myself, but they do a job and they do it well. They also just more pleasant than the RER!you mean the wide spacious quick loading 700s that everyone seems to hate? of course the natural question is how wide are the doors on a 700 compared to those on a DD RER train?
People hate 700s because they have horrible seats and they aren’t 319s.
well tbh I haven't been on a 700, I have however been on a new GWR intercity... and the seats on that were a lot more upright and less padded than an old 125.. so perhaps it's a case of the railways having forgotten the lesson learnt by their bus cousins... that almost upright seatbacks and minimal padding lead to very uncomfortable journeys... and eventually passenger loss...A very few people, many of whom are on this site. I would suggest that a very significant majority of people who use them couldn’t care less - to them it’s a train.
The newest double deck trains on the RER, the 5-car class Z22500 each have a capacity of 1337 passengers over a length of 112m. That is 11.9 passengers per metre length. The single-deck 12-car class 700 trains on Thameslink have a capacity of 1754 passengers over a length of 240m. That is 7.3 passengers per metre length.well tbh I haven't been on a 700, I have however been on a new GWR intercity... and the seats on that were a lot more upright and less padded than an old 125.. so perhaps it's a case of the railways having forgotten the lesson learnt by their bus cousins... that almost upright seatbacks and minimal padding lead to very uncomfortable journeys... and eventually passenger loss...
anyway, back to the thread in hand.... it's been quoted above that the RER DD's take about 5 mins to load/ unload... but what is the OVERALL capacity{ in passengers per hr} on those lines with entirely DD stock compared to using SDs? that, after all, is the crucial statistic to consider...
which then begs the question.... why are DD trains seen as the solution to adding capacity in foreign climbs?The newest double deck trains on the RER, the 5-car class Z22500 each have a capacity of 1337 passengers over a length of 112m. That is 11.9 passengers per metre length. The single-deck 12-car class 700 trains on Thameslink have a capacity of 1754 passengers over a length of 240m. That is 7.3 passengers per metre length.
In dwell times, a suggestion is made that a fully loaded RER can take up to 5 minutes to empty. Lets say that well trained commuters can do it in half of that time, 150 seconds. So a minimum headway of dwell plus 60 seconds (3.5 minutes) would enable 17 trains per hour giving a total passenger flow of 17 x 11.9 = 202 passengers per hour per metre length. ISTR the class 700 has been specified to enable 50% of a full train to alight and 50% to board within a single 45 second dwell which is effectively a full unload in the same time. Allowing the same headway of dwell plus 60 seconds (1.75 minutes) would enable 34 trains per hour giving a total passenger flow of 34 x 7.3 = 248 passengers per hour per metre length.
So even ingoring the effects of the restricted width of the UK loading gauge, a line served by well designed single deck trains will have a higher passenger capacity than one served by double deck trains. In addition, the single deck line will not need an oversized infrastructure, nor will there need to be special provision in every car for persons of limited mobility, (the class 700 has total accessibilty in its centre cars but a totally flat floor throughout its length allowing the elderly and those with slightly limited agility to use the whole train).
I think that the generous structure gauge has over the years allowed them to pursue the double deck solution to more capacity per train without evaluating the true capacity, i.e. the capacity of a line. The demand for space on the RER was far below current levels when the decision was made to bore oversize tunnels. Here, the option for higher and (more importantly wider) rolling stock on the UK's first two 'RER like' railways just wasn't there, at least not at a justifiable cost. So the UK has worked at the affordable features of a high-density railway that do play a significant role in delivering the continuous high throughput with typical passenger and driver behaviour, i.e.:which then begs the question.... why are DD trains seen as the solution to adding capacity in foreign climbs?
which then begs the question.... why are DD trains seen as the solution to adding capacity in foreign climbs?
Yes I agree my figures were based on a posted anecdote and I have witnessed headways closer than I've ever seen in the UK, except on LU (albeit some time ago of trains lining up at Auber with one in the platform, doors open, and the next one waiting with its cab peeping out of the tunnel ready to draw forward asap). The fact was that it was (and always will be) the passengers' behaviour that will determine the dwell time so two wide doorways serving two coach lengths of passengers cannot possibly be faster than two wide doorways serving a single flat level coach. That's ignoring the slower passengers climbing/descending the stairs.@AM9s otherwise excellent analysis makes two assumptions:
a) dwell time for the RER is based on anecdote
b) it makes no allowance for certain RER stations having two platforms per direction of line, which allows longe4 dwells.
RER Line A manages 26tph through the core in high peak hour.
Nevertheless it is all about dwell time, and single deck trains can simply have more and bigger doors. There are plenty of new and recent high capacity heavy rail metro systems around the world that have stuck with single deck, eg the Munich S-Bahn
I think we have plenty of SD buses, even on routes without low bridges. And DD service buses aren't totally unheard of on the mainland- Berlin for starters, Paris historically.out of interest... what impact would one way flow through carriages make to dwell times on DD's? what about platforms on both sides of the track? what about both together?
as I said before I find it strange that this country seems to do things the absolute opposite to the continent... we have DD buses and SD trains... and won't contemplate SD buses/ DD trains
Buses don't run with minimum headwaysout of interest... what impact would one way flow through carriages make to dwell times on DD's? what about platforms on both sides of the track? what about both together?
as I said before I find it strange that this country seems to do things the absolute opposite to the continent... we have DD buses and SD trains... and won't contemplate SD buses/ DD trains
If by this you mean the top deck empties at end A and loads at end B whilst the bottom deck empties at end B and loads at end A, then probably a bit. The problem remains though that the staircases are cramped and severely limit the amount of passengers who can leave the top amd bottom decks per minute. Also, the higher proportion of seated passengers, whilst more confortable, take longer to get up and gather their belongings and then leave than standing passengers do.out of interest... what impact would one way flow through carriages make to dwell times on DD's? what about platforms on both sides of the track? what about both together?
We do have thousands of SD buses in this country, and DD trains on regional/IC routes are limited by infrastructure - I personally think they’re a good idea on some outer suburban and InterCity routes, but we simply don’t have the infrastructure (and since HS2 has to be classic compatible, this is unlikely to change!)as I said before I find it strange that this country seems to do things the absolute opposite to the continent... we have DD buses and SD trains... and won't contemplate SD buses/ DD trains
Exactly what the DfT/NR report says, that I posted a few days ago.So on the face of it, it is very unlikely that the infrastructure on the classic network will get investment to allow double deck trains to run, especially where line capacity maximisation is the object. They just don't provide any cost-effective benefit to services that are already close to their capacity, especially on high density commuter routes.
If you want to challenge (un)loadong times, go to Paris Gare du Nord, in particular the RER platforms. It can take a good 5 mins to unload and reload a full double-decker train, which must severely limit capacity.
HS2 itself is being built to allow for double deck stock. Fact. Why do people keep suggesting it as if it’s not?What about on the high speed lines, which are built to a much larger loading gauge. HS1 could be used by double deck stock to Paris etc without problems. Loading time would not be a problem. HS2 should be built with with the possibilities of running double deck stock on the busiest sections such as
HS2 itself is being built to allow for double deck stock. Fact. Why do people keep suggesting it as if it’s not?
which then begs the question.... why are DD trains seen as the solution to adding capacity in foreign climbs?
HS2 itself is being built to allow for double deck stock. Fact. Why do people keep suggesting it as if it’s not?
I didn’t comment about the intended HS2 trains. In response to apk55’s point above, I said that HS2, the infrastructure, was being built to allow for double deck trains. Still a fact.Because HS2 trains will be built for classic compatible lines, so it'll all be very good up until Lichfield, but once it enters the WCML, it'll be bye bye bridges. Thats why they won't be DD
It's not about running more trains, the task is to carry more passengers. As this discussion has largely demonstrated, double deck trains may hold more passengers per train but normal passenger behaviour negotiating narrow stairs, queueing to get on or off and turning up on the platform in larger numbers means that the higher capacity trains cannot run as frequently as well engineered single deck trains which have a slightly lower capacity per train, (i.e. a double deck train will only give about 40% more capacity than a single deck).If you can't run more trains, doubledeckers can be cheaper than extending the platforms.
The thing is, if you design a double deck train with WIDE stairways and WIDE doors... add in a one-way flow through the carriage... and even add platform on BOTH sides of each track... then the DD train will load/ unload as fast, if not faster, than an SD train... as has been amply proved with buses the speed of boarding/ alighting has nothing to do with whether a vehicle is sd or dd but more to do with how many doors, position of doors and width of doors... in fact, as has been proved with buses an all seated DD will have dwell times shorter than a standee sd with the same number of passengers... due to the passengers wishing to board/ alight NOT having to fight their way past standees...It's not about running more trains, the task is to carry more passengers. As this discussion has largely demonstrated, double deck trains may hold more passengers per train but normal passenger behaviour negotiating narrow stairs, queueing to get on or off and turning up on the platform in larger numbers means that the higher capacity trains cannot run as frequently as well engineered single deck trains which have a slightly lower capacity per train, (i.e. a double deck train will only give about 40% more capacity than a single deck).
As for your assertion that running double deck trains is cheaper than extending platforms, that is only true if the line structure gauge will allow passage of those trains. In the UK, it would mean rebuilding most overbridges, and many underbridges, moving every platform away from the running rails and as for tunnels! Despite the need for some stations to be modified or even rebuilt, longer platforms is nowhere near as expensive unless you only consider running double deck trains across the Fens and the Somerset levels.
I think we have plenty of SD buses, even on routes without low bridges. And DD service buses aren't totally unheard of on the mainland- Berlin for starters, Paris historically.