Is this the beginning of London's RER?

And as for Crossrail, its nothing like the RER.

The main bit of crossrail is the underground bit in central london. That's huge. The underground bits of the RER are tiny, distance-wise.

They may link east and west terminals in paris, but they aren't that far apart in paris; although it would take some time to walk, its still ultimately walkable, but Paddington to Stratford is nearly 15 miles.

RER lines typically have about 2 new stations at most, linking the two halves of the existing tracks. While that's comparable with Thameslink, its absolutely nothing like Crossrail.

The surface bits of Crossrail use existing mainlines. Far from removing congestion, it just changes its destination. It even gets in the way of capacity enhancement on the great eastern mainline, because it runs down the line that the great eastern mainline could otherwise expand onto.

The RER uses entirely seperate lines that aren't just extra tracks on mainlines.

Crossrail isn't like the RER at all.

I believe Crossrail & Thameslink are very much like the RER in that they connect commuter rail services in the outlying areas with express cross-city centre service. Whether the latter is in tunnel is immaterial.

That is more to do with the geography and history of Paris compared to London. Central London has always been much wider, east to west, than Paris (look at the shape of the Circle line on a geographical map).

Walking from Euston to Charing Cross is quicker than from Gare du Nord to Gare de Lyon.



But the tracks used by Crossrail will still have had a similar service to now. Running more trains on the slows to Shenfield would have the same problem whether or not Crossrail was running.



The RER lines DON'T use entirely separate lines. Much of lines A, B & D, a bit of line C and nearly all of line E are on shared routes with mainlines.

No. It was designed to make better use of existing minor lines that cut right into the centre of Paris by linking them together. Its purpose wasn't to allow people to stay on mainline trains through the city without, this was merely a consequence.

They had some lines that they wanted to make better use of, rather than being trying to find ways to keep people off the metro.


Bastile station? Invalides?


I was under the impression that was something to do with the geology of the area.


I don't see why.

I really don't see this obsession with having mainline train routes through london. The RER doesn't go much further than the london tube. Even Crossrail is basically a jumped up tube line.


The Paris metro use rubber tyres, and consequently manage to have much shorter gaps between trains. That, and more trains. In london we have quite expensive drivers and normal metal wheels, so its slower and there are less trains. If we changed over to paris train conditions on the same london lines, we'd have double the capacity too.

Except for the fact that Bastille station closed before RER line A opened and so Metro line 1 was taking all the load instead. Invalides may have been a quieter terminus, but Quai d'Orsay at the other end of the new section wasn't. (Brian Patton's book stating 24 tph from Orsay compared to 8 from Invalides before opening).



The RER does penetrate considerably further than the London tube lines (although not the Met Line). The point is that mainline trains have several times the capacity of any tube train. A regular train I get into work is 12 cars long and so is nearly twice as long as a 2009 or S-stock train; there is no way that a tube train can take nearly as many passengers. Then the double deck RER routes can take even more passengers than the UK mainland stock.



The rubber tyres are not the main reason for the shorter headways, but the shorter trains, different signalling and terminal layouts are. There is no way that the Metro has double the capacity of an equivalent LU line.

A couple (maybe 2 1/2) of points on the thread so far:

- 12 car mainline suburban trains contain about 1450 people (that's, for example, what Bombardier were offering for Thameslink, and that required the odious 3+2 seating and assumed that trains were loaded to 115% of seats); that's probably about twice the crush load for a tube train (although I have seen figures approaching 1000 per 6 car for the sort of loads where the punters are carried past their stations unable to get off). In both cases, the maximum official load works out at about 7 punters per metre length; in the LU case, not many of them sit down, however. 12 car RER (and eg Zuerich S-Bahn) double-deckers can take up to about 1700 punters - not much of a gain because so much capacity is lost in the stair wells.

- I always understood that the use of rubber tyres by RATP reflected the close stop spacing on line 1 and the need to accelerate/brake faster (and spread to those other lines where adhesion was a problem, plus line 6 which has some elevated sections close to housing, where noise is an issue).

- In terms of headways, RATP say they rely on their countdown clocks at the platform ends to get down to 95 seconds (about 42/43 tph) with the drivers instructed to shut and go on the dot regardless (just love those train door edges). LU carried out an experiment some years ago on (I think) the Northern in which they achieved a similar result by throwing everything they could at it (stepping back, platform control etc) and with the then conventional signalling. Although they didn't think they could sustain this indefinitely, I see from my 1970 tube timetable that the Bakerloo offered a service interval of 1 1/2 - 2 minutes in the peaks which is presumably equivalent to something like 36-38tph. Pretty impressive.

Graham H

PS The Berlin S-Bahn claimed 60 tph with steam traction and conventional semaphores but how station dwell times were managed is anybody's guess as they were using slam door stock. The Moscow metro also claims 60 tph. Door control there is aggressive to put it mildly. But not a rubber tyre in sight...

slugabed - quite agree. In fact it was the Southern management's argument that a train could be emptied so quickly that kept airdoors away from SR for 40 years after everyone else had adopted them, but that applied to termini to minimise platform reoccupation times. Staff could then go round and shut the doors at "leisure". The puzzle with the Berlin S-Bahn was how that was done on through stations unless they had several platform staff per coach who would spring into action.

You are quite right about the effect of safety on train dwell times - the audio/safety actions for the new Thameslink stock were identified as comprising 17 different activities to open and close the doors which in total occupied about 20 seconds between train stopping and brake release to start- and DfT were demanding no longer than 45 second dwell times in the central area. Perhaps they had in mind Japanese style white gloved pushers...?

GH