Length of Class 345

fleetline (Yes, I suspected you worked for Interfleet!)

Interesting - generally you make a number of points that were not made to the rolling stock bidders at the time they bid. It's not of course, your fault, but I do think that DfT are placing themselves in a very dangerous position by moving the goal posts after the tender award; at the very least it opens them up to legal challenge. It is also very poor procurement practice and in certain jurisdictions would be seen as corruption...

To the substance - Depots - had the bidders known that Dft was prepared to be flexible, I can think of at least one that would have preferred different solutions at different locations. Hornsey is too "central" and Three Bridges has (or at least when I last saw the plans) an awkward manoeuvre to access it. I was also interested in the proposed fleet mix and surprised at the number of 8 car sets - again, if the potential franchise holders had a free hand, I think the proportion of 8s would be very much less (on the assumption that they would terminate the Wimbledons at Blackfriars.)

32 tph? I suspect that most bidders had assumed that when this proposal last died in c2005, it had gone for good. The non-ATO preference assumes only 24 tph; clearly at 32, manual isn't really an option.

Dwell Times - we are in fact saying the same thing, divided by terminology. I was focussing on the time the train was stationary which is what ultimately conditions boarding times, which was the point at issue. I think we both agree that 45 sec dwell is just about do-able if everything goes according to the theory. However, experience as an operator suggests that there will be a high incidence of unpredictable "events" such as minor trips, passengers with luggage/children, and so on, which will all be sources of minor delays; it requires only 2 or 3 such events amongst 1000 disembarkations to hold things up... I agree that 90 sec dwell times with 32 tph would be intolerable - there'd be only 22 sec between the train moving off and the one behind arriving at the platform.

17 door operations - no, I wasn't given a list unfortunately. When I quizzed the train manufacturer who had raised the point, he mentioned a sequence which included door release, door opening initiated, acoustic signal, door movement, as well as the various manual checks to be made by the t/o or guard and so on but I wasn't given the exhaustive list.

Disabled requirements - I was interested by the implication that having a special area for the disabled might reduce the need for some of the PRM requirements throughout the train. The precedents for that are not good and I think a short visit to Switzerland (at the clients' expense, of course) would tell you a sorry tale in that respect.

GH

A propos your last point, I was thinking that you had in mind the possibility of avoiding such distributed facilities for the disabled as acoustic arrangements etc. Concentrating the disabled loos in one place probably won't prevent some disabled (eg blind people) being widely distributed throughout the train with the obvious consequences.

A propos the depots, the rolling stock bidders were certainly responsible for delivery of the construction but they were given a very firm steer to choose Hornsey and Three Bridges - and in a defined layout -in preference to anywhere else such as Bedford; effectively, they were told that they would get no help from DfT if they chose anything else. They were also told in no uncertain terms as to the degree of flexibility that they wouldn't have in accessing the depots. In any case, that's not the only thing that seems to have changed in the last 18 months - the revival of 32 tph for example.

GH

? I would read the text you quote as meaning that the core frequency would be 24 tph and that 45 sec was the minimum station dwell time, with 60 sec as a margin not to be relied on for planning purposes.

Sorry - I never suggested that anyone's trains couldn't manage 32 tph, merely that the idea (a) was part of the original spec from the time we first planned the route, but (b) as your extract from the ITT says, not a formal requirement at the time the manufacturers were required to bid. The thing the manufacturers (all of them) focussed on was the 45 sec minimum dwell. So far as I know, all of them expected their product to achieve that. Whatever made Siemens the preferred bidder was not their superiority in that respect.

I do not, nor ever have, worked for any manufacturer, but I have worked on the project in various ways since its inception so I have been able to follow its history closely. So far from being some "eternal" plan, it has changed its nature and scope quite radically over the last couple of decades, even alas after the men in hard hats had already started their work.

Did I say that the Desiro couldn't achieve a 45 sec dwell time? Did I say I didn't know what made Siemens the preferred bidder? This is a very tiresome game and I frankly can't be bothered to deal with your twisting of my words any more.

Goodbye.

Somehow, the thread got hijacked into a surreal TLK discussion, but back to the "res" - the point about having to cope with high numbers of both exiters and boarders is going to be key, as you say. The best solution - but it's far too late for that - would be to have separate platforms for boarding and leaving - something that RATP regretted not doing hugely when designing the RER. No doubt the cost would be enormous... The problem with wider doors in this respect is that it leaves less room for the waiting boarders to stand aside on the platform without blocking these selfsame doorways.

GH

Are there going to be platform doors? As these should help a little bit with the door blocking problem, but at stations with very large numbers of passengers waiting to board there will come a point where there isn't physically space for all intending passengers to wait between doors without blocking the exit from the platform. Separate platforms would have been ideal, as I can easily see that right from the start of the service there will be a need to restrict access to some platforms during times of disruption to allow space for alighting passengers to safely leave the platform.

With such tight dwell times it's going to be important to get the platforms clear of alighting passengers as quickly as possible, and not have people hanging around looking for where they need to go to leave the station. A direction sign opposite the exit to each platform would be ideal (but unlikely to be provided). Would it be possible for on-train announcements to say something like "the next station is Farringdon, where the doors will open on the right hand side. The way out at Farringdon is towards the front of the train." The latter could be different for each car where the exit is in the centre of the platform.

Double-deck stock. No, unless it can be fitted within the existing loading gauge.

Two platforms. Not that I am aware of, but it is something I've often thought would be beneficial on high throughput lines.

The tunnels are 6m diameter. That's not enough for "full height, full width" double deck stock. It is enough for designs which involve compromises to fit within the available kinematic envelope.

As for bifurcated platforms (where a single track divides into 2 platform roads, allowing train dwell times to overlap), LB will indeed have these as a result of TL work - but not on the TL pair of tracks. The bifurcated platforms will be on the Cannon St route.

Indeed. The platforms on Crossrail will be 1100mm arl. This would mean a bespoke design with compromises, as I said - in this case, the lower deck limited to something like the proposed LSVG-8.

Also, just because the tunnel diameter is 6.2m (and allegedly useful dia is 5.9m after allowing for alignment error??), doesn't mean that the rail level above the invert is low enough, nor the overhead contact beam high enough for full height DD stock with 125mm clearance for 25kV. The DfT have clearly stated that the OHCB will need to be raised for DD in the future - that probably means constrained upper deck design. Again, back to a bespoke design with compromises.

The width might be though - I think the RER loading gauge is about 30cm wider than your typical British train.

It's a new line only in the central section. It needs to be compatible with the platforms at suburban stations at both ends of the route, which will all be ~1100mm. At least some of these platforms will also continue to be served by non Crossrail trains

This rather dry link "Guide to British Gauging Practice" from the RSSB website has some interesting snippets in it, including:

So, 1100mm has been used for new passenger only lines that also need access to the classic network at large - Crossrail easily fits that bill.

I also get a sense from some of the diagrams in it that the French width dimensions given above will still be a few cm too wide for current loading gauges, although maybe not beyond what could be cleared with a big bucket of cash. It's academic anyway, given the height issue is more significant.

I'm well outside the breadth of my understanding of loading gauges now, and need an expert to come and rescue me...

Its quite common that platforms though lower than carriage floors are closer to the train horizontally. In order to not impact on the side of the train they cant be both as close and of the same height, it was probably felt that reducing any horizontal gap between train and platform was safer than reducing the step up because many train doors had grab rails by them and tread/step plates/boards to enable someone to climb up into the carriage. Another advantage of this approach is that it works on curved platforms too, whereas trying to maintain a level access can lead to large horizontal gaps between the doorways and platform edge, necessary for the arc formed by the train carriage moving along the bend.

Theres a great picture of CO/CP stock at Watford somewhere showing how the flare of the stock hung over the top of the platform, creating a small step, but no gap whatsoever.

It is ironic that in order to introduce level access to all platforms that there will be some curved platforms where safety will actually be decreased.