Express Rail Tunnels and Regional Rail Capacity

In three cities that I know of, there are plans to deal with an incipient regional rail capacity crunch by building a new tunnel: Tel Aviv, Hamburg, London. The route in question in all cities already has regional rail service making frequent urban stops as well as longer-distance intercity trains. Setting Tel Aviv aside – new tracks are not necessary there at all – both Hamburg and London have a choice of what to build in the tunnel. In both cases, the answer must be intercity rail and not regional rail. This affects Crossrail 2 in London, currently shelved but still in active planning, as well as plans for Hamburg Hauptbahnhof-Altona capacity improvements.

The dominant factor in the cost of an expensive urban railway in a constrained environment is the stations. Low-cost countries build very cheap stations, but that’s true in outlying areas, urban as they may be, and not in city center areas under and around older subways. What’s more, Britain and Germany are not low-cost countries. German costs are somewhat higher than the global median, British costs among the world’s highest. Thus, keeping down station costs is paramount – and express tunnels have fewer stations than local tunnels.

Normally, the express vs. local issue is not relevant to a new urban rail line. Yes, more stations are more expensive, but on a line designed to open up service to a new area, more stations also provide more access, so the extra cost is often worth it. This is true even for urban subways that act as relief lines, like Second Avenue Subway, a relief line for the Lexington Line: more stations provide better local access and therefore increase the line’s relief value.

However, when the problem comes from regional or longer-distance capacity, all of this goes out the door. Crossrail 2 includes a long tunnel from Central London all the way to Wimbledon not because of purely local needs but because of very high rail usage along the South West Main Line. In Hamburg the problem is similarly about the main line between Hauptbahnhof and Altona – local traffic is saturated on the S-Bahn, and all other trains have to squeeze on the remaining two tracks of the Verbindungsbahn. Thus, capacity expansion should involve a tunnel with the fewest number of stations, on the most express services.

And yet both cities are doing it wrong. Hamburg is planning an S-Bahn tunnel, with the existing S-Bahn route then given over to regional trains, to be segregated away from the intercity trains. But there are already two Hauptbahnhof-Altona S-Bahn routes – that’s not where the service need is. Instead, new tunnels should go between the stations without stopping, to reduce costs, hosting intercity trains while regional trains take over the existing intercity tracks.

London is likewise planning on an undulating connection between Clapham Junction and Wimbledon, with links to other parallel north-south lines in the area. This is not good planning – those new stations are inordinately expensive and not needed for network connectivity. If there is no way to six-track the South West Main Line above-ground by replacing the sloped berm with retaining walls, it’s the fastest trains that should go underground, to save money on stations. Crossrail 2 is a £31.2 billion project; I don’t think Paris has spent this money on all Métro and RER lines in the region to date combined, and Grand Paris Express, at a broadly similar cost, includes 160 km of tunnel. It’s necessary to economize and build the tunnels that are necessary, and not the ones London would like to have.


  1. ant6n

    In general, your point may make sense. But there may be other benefits to consider.

    For Hamburg, other benefits of building that rail tunnel as an S-Bahn is that it allows changing the location of the city-tunnel S-Bahn stations to better connect to the subway network. It also allows not only to kick out the S-Bahn out of the Verbindungsbahn tracks, but the Hauptbahnhof station. This means more long distance platforms, on top of the extra tracks — if that was done using a high speed rail tunnel, it would require a much larger tunnel station (probably 4 tracks instead of 2, 400m instead of 200m).

    So the trade off is really 1 underground intercity station vs 3 undertround S-Bahn stations, but with better connectivity. It’s not so obvious.

    • Alon Levy

      Does Hamburg Hbf need more tracks? Right now it has 8 mainline tracks and 4 S-Bahn tracks, which should be enough for 6 approach tracks and not just 4.

      • ant6n

        The problem is that Hamburg is operated like 2 terminal stations, connecting West and East – for regional rail, platforms are even split in half and trains from both West and East use it at the same time. But through-running is not so easy (besides the agency issue where Hamburg state is on the border of Niedersachsen and Schlewswig Holstein), since traffic on the East side is heavier than on the West side (compare Deutschland Takt plan, with more trains going to Luebeck, Berlin, Hannover than up North).

    • Matthew Hutton

      I believe the flaw is that you’d need to start dropping down pretty early anyway to go under the river Thames in a tunnel.

      • Eric2

        You can go over the Thames on existing tracks. From there it’s ~1km to the station, plenty of space to drop down into a tunnel.

      • Eric2

        Why should rebuilding an above-ground station be particularly expensive? Just move the tracks and platforms, maybe build some concrete ramps for a flyover.

        • Alon Levy

          Because this above ground station is horrendously complex. Els don’t cost zero; els in an environment where they go over other els cost not much less than subways – see for example the Tokyo-Ueno Line slog. Of course it’s still nothing compared with XR 2 tunneling cost, but this isn’t free.

          • Eric2

            Seems to me most of Clapham Junction would be better classified as an embankment rather than an el? In any case it’s a pretty spacious environment. Looking at a map now, no flyovers should be necessary, just cannibalize part of the depot space for 2 more tracks.

          • fjod

            You need a flyover to get from the SWML, which comes in at the north (of the southern half of the station), to reach the line into Victoria, which branches off to the south at a junction to the northeast of the station. This is what I referred to in the linked thread as “the added complexity of threading this line through operational lines in Battersea”. I’ve absolutely no idea what’s underneath Clapham Junction given how old and incrementally-built it is, but it’s definitely got some of both viaduct and embankment. There is definitely at least one tunnel underneath the platforms.

          • Matthew Hutton

            Do we know how much of the crossrail 2 tunnelling cost is the angel to Victoria section which i would expect to be complex and expensive given the other tunnels in the area and how much is the Victoria to Wimbledon section which I’d expect to be significantly cheaper – albeit with pretty high costs at Clapham junction itself.

          • Sascha Claus

            You need a flyover to get from the SWML, which comes in at the north (of the southern half of the station), to reach the line into Victoria …

            Which line to Victoria, the Brighton Main Line? Do you want to mix trains from Brighton and South Western Main Lines?

    • marvin gruza

      Setting Tel Aviv aside – new tracks are not necessary there at all……………..please write more about this, especially given projected population figures over the next 30-50 years.

  2. Phake Nick

    What about Seoul’s GTX approach? Those will be underground mainly for regional trains, but they will have very limited numbers of stops.
    And what about the planned, but probably never going to happen, Keiyo line extension via Shinjuku to Mitaka in Tokyo, acting effectively as two extra track for the Chuo Line? If it ever get built it will probably be for regional trains with a number of underground stations along the line too.
    Although at that time, there will probably be minimal amount of long distance train on Chuo line, as Chuo Shinkansen will most likely be opened by then.
    But then, in Tokyo, was the decision to build Tsukuba Express line as an alleviation of Joban line a proper choice? It was, at least, mostly overground
    On the other hand, the planned new underground tunnel connecting Keikyu and Keisei through Shin-Tokyo station is in line with the idea of redirecting trains with limited amount of stops to the new tunnel/

    • Andrew in Ezo

      The Keiyo Line already has a physical connection to Shinjuku and western points at Shin-Kiba via the Rinkai Line, and though not currently used, the tracks are there, you can even see them on a satellite view. But such a regional/intercity route would be pretty pointless- the overwhelming majority of regional users are either going to or from central Tokyo, not riding on a long, thin route (to borrow from airline terminology) from some waterfront development on the edge of Tokyo/Chiba to say Kofu or Matsumoto.
      The Tsukuba Line is a success- year on year ridership growth since opening (395,000+ daily ridership pre-covid, 100K more than the total daily ridership of “Big 16” railway Nishitetsu in Kyushu) and a major catalyst in development of railway suburbs in Chiba/Ibaraki. By this metric it was good choice.

      • Phake Nick

        The point of the project is capacity, especially capacity along the Chuo line, which is something obviously cannot be provided by extending service via Rinkai line into Saikyo line given Saikyo line’s frequency.
        Secondary goal of the project is to better connect both Chuo line area and Keiyo area into central Tokyo.
        Official documents doesn’t mention anything about connecting Western Tokyo with Chiba, at most it only mention forming an lateral axis comparable to Ueno-Tokyo Line and Shonan-Shinjuku Line.

        As for Tsukuba line, yes it can be said as a success in itself as a transit project and as a project to trigger transit-oriented development along the line, but then the question is whether this is the best spend of money to spread out the commuting demand on other lines in Kanto area?

      • Phake Nick

        Also, as mentioned in the PDF I linked below, one major problem with Keiyo-Rinkai through running is fare calculation.
        Because if a passenger from Shinjuku take a through-running Rinkai train to Chiba, there are no way to tell whether the passenger actually took the Keiyo line via Rinkai line, or did they took some other lines like Chuo-Sobu line to reach their destination. It make it impossible to judge how many revenue should JR pay to Rinkai, with the fact that Rinkai is a separate company in mind although it’s affiliated with JR East.

      • yuuka

        JR East should just buy over the Rinkai Line, ’nuff said.

        As for the Keiyo line extension, I consider it quite natural to think some stations could be built between Tokyo Station and Shinjuku (and perhaps between Shinjuku and any Chuo Line merge) to provide subway connections – at the very least, one in Yotsuya. The best route is already occupied by the Marunouchi Line, but any more capacity to relieve the Marunouchi Line, even as a deep level bypass, is a good idea given that route’s relatively tiny trains.

    • Alon Levy

      I think GTX is more about expanding access with through-running than about relief for congested lines.

      The Keiyo-Shinjuku extension looks like vaporware right now and I can’t tell what’s JR East and what’s railfans, but I think the proposal is stopless? (And this, to be clear, is bad – a few stops are enforced by network connectivity needs, but Tokyo notably doesn’t care with its express bypasses and is the world’s #2 city in missed urban rail connections after New York.)

      • Phake Nick

        In Seoul, they wouldn’t need to build new lines if they can fit express trains into existing rail lines.

        As for the Keiyo-Shinjuku extension, it was first proposed in the 1970s and with plan being made in 1980s. It was when Japanese economy still growing rapidly, population influx into Tokyo at very high rate, and when the rail network was still nationally operated under JNR, with the plan for Narita Shinkansen still haven’t dead yet. Which are all massively different from the Tokyo rail network we know nowadays.
        However, this line continue to survive in following planning documents for railways in Tokyo. Japanese national government form rail plan for metropolitan area every 15 years, with the line first appearing in year 1985’s plan, then in year 2000’s plan the line was ranked with importance of “A2”, aka “It’s appropriate to prepare for the construction of such line in the next 15 years”
        Then in the year 2015 plan, it no longer gave rank to different projects, however the national government analysis claim extending Keiyo line to Mitaka will have a Benefit/Cost ratio of 1.4-1.6, and an EIRR of 6.3%-7.1%. In addition to quadruple-tracking Chuo Line Mitaka to Tachikawa segment, which will have a Benefit/Cost ratio of 1.7-1.8, and an EIRR of 7.9%-8.4%. However, extending Keiyo line to Mitaka underground is expected to cost 450 billion yen, and quad-tracking Mitaka to Tachikawa is expected to cost 360 billion yen, and both projects are expected that they will not be able to recover the project cost financially within 40 years after they open in case they’re being constructed, and thus they’re being deemed not worthwhile by the Tokyo government in a separate analysis also in 2015.

        But still, in year 2018, the government of Tokyo picked 6 rail line projects, and created a fund for these projects, intended to deposit excess amount of money in their city government budget from profit from Tokyo Metro Co Ltd into such fund in order to pave way for construction of such line into the future. The extension of Keiyo line to Mitaka with the accompanying Chuo Line quad tracking between Mitaka and Tachikawa are two of the six projects being selected. The other four projects are Haneda Access Line, Kamakama line, quad-tracking Keio line, and the construction of a new loop line around 23 wards, branded as Metro Seven and Eight Liner. However, since all six projects come together would cost up to almost 3 trillion yen, and the amount of money they’re putting into in 2018 when they created such fund was only 62 billion yen, such effort of financing new lines is not expected to yield any actual progress anytime soon.

        More recently, the Japanese national government have been trying to privatize Tokyo Metro, using the fund earned from such privatization on revitalization effort on area hit by the 2011 Tohoku earthquake, and the way the discussion is currently heading to now is that both the national government and the Tokyo city government will sold half of their stock of the Tokyo Metro. Tokyo city government intended to use the fund earned from selling the Tokyo Metro to construct new metro lines, but the primary targets being listed are extending the Metro system to Shinagawa enhancing its position as a transportation hub, as well as the construction of Toyosumi line, filling in a missing link in the metro network on the East side of Tokyo.

        One thing that should also be mention is that, JR East itself are trying to introduce longer trains on the Chuo line, although the added train cars will be premium cars, hence its effectiveness in reducing the line’s overcrowdness are still pending observation.

        I don’t think there are mentions of how many stations will there be on these planned lines, since those plans only represent key connecting nodes. But given the plan is to build the extended line as an subway, I think it will have station density comparable to regular subways? Specifically since one of the project goal is to improve Western Tokyo as well as Chiba’s connection into Central area of Tokyo. If it’s just Tokyo station and Shinjuku station then that wouldn’t make sense.

        Conceptually I think it can be think as similar to Tokyo Metro Tozai Line?

    • Borners

      As Alon said in their London crayon, London has lots of branching, the problem is lacking central arteries that can relieve pressure on terminal platforms and create more 1 seat cross-city rides. Seoul’s through-running subways give them the basics of that. GTX is an express system (its also because they kinda screwed up KTX terminals). Seoul doesn’t have the fast cross-city legacy regional rail lines that Japanese cities have with JR’s Special Rapid Service/Ueno-Tokyo line etc. GTX is making up for that.

      Tsukuba Express is a different case from Crossrail. Its middle sections in Moriya-Kashiwa-Nagareyama-Misato were not just about relieving the Joban line, it was about creating new suburbs too, as well as connecting Tsukuba directly to Tokyo by rail. Its underbuilt for sure but there are no more easy connections to be made on the other side of the CBD because Tokyo Metro/Toei have already done so! Not that expanding it south wouldn’t be a good idea. The closest thing to Crossrail in Japan is the Hanshin-Kintetsu connecting line through Osaka.

      Keisei Ueno to Keikyu will turn the Keikyu line into reverse branching hell!

      • oevans82

        In theory, there are three western tails to and three eastern tails to the standard gauge Keisei/Keikyu/Hokuso/Asakusa etc lines.

        Western: Asakusa Line, Keikyu Line, Kesei Main Line (Ueno Segment)
        Eastern: Keisei Main LIne, Hokuso Line, Shin Keisei Line

        My “dream” crayon would be to deinterline it all into three coherent through lines. The only place where all three would meet in one place would be Keisei Takasago Station.

        The general plan would be:
        (1) Asakusa Line Keisei Oshiage Line Eastern end of Keisei Main Line
        (2) Western (Ueno) end of Keisei Main Line Keisei Kanamachi Line Shin-Keisei Line
        (3) Keikyu Line New connecing line Hokuso Line

        (1) Already exists in full.
        (2) Would require a reconfiguration at Keisei Takasago to allow the Ueno segment of the Keisei Main Line to run through onto the Keisei Kanamachi Line, which would be elevated and double tracked, and a ~4km new line from Kanamachi to Matsudo.
        (3) Would require a 17km express line from Sengakuji to Keisei Takasago, with 2 stops: Tokyo and Oshiage. The southern portion, Sengakuji – Tokyo – Oshiage has been present in official planning documents for some time; the addition here would functionally amount to quad-tracking the Keisei Oshiage Line with no intermediate stops between Oshiage and Keisei Takasago.

        Where does this fall on the list of Tokyo’s transportation needs, probably not very high. But what is a crayon, anyway, if it’s actually realistic?

        • Borners

          I’d be happy just with an extra set of platforms at Takasago so they could run more Hokusou line services. Takasago station could use a facelift too.

  3. df1982

    Where would an intercity tunnel under London go? There aren’t really all that many destinations south of London that are beyond the perimeter of a regional rail catchment. Brighton, Southampton and Portsmouth are borderline, so it would really just be Bournemouth. Exeter and Plymouth are also in intercity territory, but they run to Paddington. So you’d have a major demand imbalance.

    Of course there’s Paris and the continent, but the Eurostar runs to St. Pancras from the north-east. If you’d have your time over, you might want to have Eurostar using underground platforms at St. Pancras approaching from the south, so you could run through to HS2. But that ship has sailed. As it stands now there won’t be any physical connection between HS1 and HS2. The chord at Camden was canned due to local opposition, and so was the mooted people-mover between the two termini. So at the moment the guidance will be to walk the 750m.

    • Eric2

      The southwest cities (Portsmouth, etc) pair reasonably well with the northeast cities (Cambridge, etc). Whether you want to call these regional or intercity, they call for the same kind of service. At the same size/distance, you have Oxford and Milton Keynes vs Ashford and Canterbury. This too matches pretty well. You could build tunnels to connect these pairs of destinations – these tunnels would naturally have fewer stops than Crossrail or Thameslink.

      This leaves the “real” cities – Bristol, Birmingham, everything north of Birmingham – which have no pair and have to end in a terminal like Euston, St Pancras, or Paddington. But everything else could be through-routed in tunnels with a minimum of stations. For example Victoria and Waterloo stations currently have a total of 42 platforms, that could be reduced to 0 above-ground platforms and ~10 underground platforms.

    • Alon Levy

      The XR 2 replacement intercity tunnel wouldn’t be for long-distance trains but for RegionalExpress-scale trains on the SWML – right now there’s already heavy traffic on the line heading out of London, so finding a route for a two-track tunnel without stations for those trains and then increasing local service on the existing lines should be workable.

      • Richard Gadsden

        It would definitely make far more sense to route the SWML trains (to Southampton and Bournemouth and Poole) and the PDL trains (to Portsmouth) into the tunnel. The WEML trains (to Exeter, via a secondary route), would be more difficult to do, as you’d need either to electrify 195 km of track from Basingstoke to Exeter, or you’d need to build trains specific to the route (they would need to have diesel engines and two types of electrification; technically possible, but no such train would be needed anywhere else in the country, so they would be rather expensive).

        You would only need two underground stations – one at Waterloo and the third at whichever North London terminus you hook in. Considering that the MML and ECML outer suburbans are already on Thameslink, and considering how crowded Euston is due to be with HS2, it would make sense to relieve Euston; trains to Northampton and Milton Keynes and Coventry would fit well with Southampton, Portsmouth and Bournemouth.

        Current service pattern is (north): Hourly to Milton Keynes, Northampton (via Milton Keynes), Birmingham (via Milton Keynes and Coventry) and Crewe (via Milton Keynes) for 5tph
        (south): 3tph to Portsmouth, Hourly to Weymouth and Poole (both via Southampton and Bournemouth), also 5tph.

        The Waterloo services are limited in frequency by access to the Waterloo approaches and platforms, which this would relieve; the Euston services are limited because they share tracks with intercity services to Birmingham, Manchester, Liverpool and Glasgow. HS2 will transfer most of those intercity services onto the high-speed tracks, there would be plenty of capacity to raise frequencies on both lines.

        This would also reduce above-ground non-high-speed services to Euston to just the Watford DC lines (London Overground), the 2tph Tring local service (serving suburban stations that the expresses skip), and whatever residual long-distance service survives HS2 to serve intermediate stations – probably four tph (one each to Manchester, Liverpool and Chester, plus the Birmingham/Glasgow service), which would release much more space at Euston for HS2 platforms.

        • Richard Gadsden

          Aaargh, not “the third” at Euston. I was originally thinking you would need a station at Clapham Junction, because the SWML trains mostly stop there also, but I’m not convinced you do. I’d need to look at the actual travel patterns and how many people on those trains use Clapham to transfer (to Victoria, or to outbound services that originate from Victoria, people who currently transfer onto trains from Waterloo can do so at Waterloo).

          If you were to build that station, then the Northern Line extension from Battersea Power Station Station to Clapham Junction would make sense to do at the same time so both sets of underground construction are done together.

        • Matthew Hutton

          You could definitely justify electrifying the Dorset mainline to put a Andover to Exeter motor-rail in place so you don’t have to build the phenomenally expensive Stonehenge tunnel on the A303 that’s been blocked by the judges.

      • df1982

        OK, I get this. I tend to conceive of London as having a three-tiered network:
        1. Underground
        2. SE regional rail (Overground, Crossrail, Thameslink and short-haul terminating services)
        3. Intercity

        But what you’re proposing is to break category 2 up into S-Bahn and Regional Express style services. Crossrail 1 and the Overground are S-Bahn (the latter being similar to the Ringbahn in Berlin), whereas Crossrail 2 should be RE instead of another S-Bahn. True Intercity would still run to the termini.

        How does Thameslink work in this typology? It goes much further than a normal S-Bahn (Brighton to Bedford) but has S-Bahn style operations in the trunk.

        • fjod

          It’s already broken up into those categories: you can usually divide outer suburban services, which skip most stops in London (e.g. services to Southend Victoria, Hertford East, Alton, Basingstoke, Tring, Tattenham Corner, Dorking, Thameslink to Brighton and Bedford), from all-stops suburban ones.

      • Rational Plan

        Not sure, long distance commuter trains don’t have much standing space as people want seats over such distances. Does not mesh well with cross city tunnel traffic needing quick loading times. ( I know! Thameslink, but people question the distance that line covers.). Plus express trains only stopping at existing terminals before crossing the centre, creates a distribution problem. The tubes are full from those central London stations, it’s no good getting even more people to them if there is no space on local underground lines. You would need some additional central London stations, so that commuters can catch a train direct to most destinations without having to switch to the tube. It can be argued that outside central London crossrail 2 has had many more inner stations added and extra miles of tunnel to try and solve all congestion problems on existing lines that the new route would go near, vastly inflating it’s cost. But when you’re convinced you only get one meg project at a time, then everyone wants each one to solve all problems.

        • Alon Levy

          Yeah, so the trick is to build the cross-city tunnel for urban service and connect that to the slow tracks of the SWML, and then move the longer-distance regional trains to a stationless tunnel between Clapham Junction and Raynes Park (or Wimbledon if you can six-track Wimbledon-Raynes Park above ground) to connect to existing lines to Clapham and thence Waterloo.

    • Alon Levy

      It’s long overdue. The S-Bahn tunnel in Munich is far and away the busiest in the German-speaking world – it has maybe twice the ridership of the Stadtbahn here – and has the world’s highest tph count of any mainline two-track railway with stops. It needs extra capacity – and the second tunnel wisely runs a bit more express. Costs remain very high – it may overtake the RER A as Continental Europe’s most expensive tunnel per km – but this is a) genuinely difficult city center construction and b) Germany having its own cost disease.

      • Subutay Musluoglu

        Thanks. Was not aware that Munchen’s tunnel throughput was so high. I always assumed RER A held the record. BTW – On costs per km, did you mean to say higher the RER E extension’s current costs, or were you referring to RER A’s original capital costs from the late 1960s through the 1970s?

        • Alon Levy

          The RER A holds the record in Europe measured in passengers per hour; Tokyo and (I think) Mumbai both beat it. But the RER A is down to 24-27 tph because of long bilevel dwells, whereas Munich is still 30 tph.

          Costs per km are adjusted for inflation and refer to the RER A’s central segment between Nation and Auber; I don’t know how much La Défense-Auber and Vincennes-Nation cost. The RER E is not that expensive – it’s around $300m/km, with expensive stations at wide spacing.

  4. Herbert

    Tel Aviv might not need new tracks for capacity, but having a main station not buried inside a traffic sewer at the urban outskirts sure wouldn’t hurt…

    • Alon Levy

      Most high-rise construction is pretty close to the stations at this point – the original city center was in district 5, centered around Rothschild Boulevard and Shalom Meir Tower, but it’s migrating east to Namir Road and to some extent hopping the border over to Ramat Gan. Israel has huge walkability problems near the train stations, but TOD plus the odd elevated walkway are making that not so bad around Tel Aviv Center and HaShalom; the bigger problems are elsewhere, with park-and-rides at the outskirts of built-up areas like Rishon, Ashdod, and Netanya.

  5. Mikel

    You’ve previously mentioned that the ship for a “Paris Hbf” sailed when Chatelet-Les Halles was built as a RER-only station. But nowadays, at which cost do you think it would be worthwhile to bore a stationless tunnel linking Gare de Lyon to Gare du Nord? And Gare de Montparnasse to Gare de l’Est? How many underground platforms would be needed at either end? (In Madrid the Chamartín-Atocha tunnel is to get 4 underground platforms at Atocha, but its potential traffic is, I assume, much lower than that of a Lyon-London/Amsterdam/Köln connection running through Paris.)

    • Alon Levy

      A stationless tunnel would not really be useful, because the platforms are right against the bumpers, so that the tunnel would not be able to incorporate it.

      What I think would be useful (and also cost a few billions) is building those two tunnels but then also building a cut-and-cover station box with platforms around Gare du Nord, a project of similar complexity to the original Les Halles RER station. The even fancier way of doing it is to do the same but also include station boxes at Gare de Lyon and Gare Montparnasse. The big issue is that it requires thinking about fleet replacement, because the TGV Duplex has horrendous circulation, as it’s designed for nonstop service between cities with large legacy terminals; I’ve seen it take 10 minutes for the train to clear at the Paris end, and no such tunnel should be considered without a plan to cut this to at worst 5 minutes, ideally 2-3 minutes.

      • Alex Cat3

        Looking at a google satelite map it would seem to me that with electrification of the Petite Ceinture and a simple track connection near Gare de Lyon TGVs now coming into the Gare du Nord could be rerouted over the Petite Ceinture to Gare de Lyon.

        • Eric2

          Wouldn’t it be better the other way – have all trains end in Gare du Nord, which seems to have the more desirable location? Anyway you would still have the issue of the station being a dead end, which severely limits capacity.

          • Alex Cat3

            From google satelite view an overpass already exists allowing trains coming towards Gare du Nord to be routed onto the petite ceinture. There is also a ramp leading off the Petite Ceinture towards the Gare de Bercy, though the tracks that lead off the ramp abruptly end instead of going to the station. Both of these could be used in conjunction with a new overpass connecting the end of the ramp to Gare du Lyon. Alternatively, you could try terminating all the TGVs at Gare de Bercy, which would require no overpass but Bercy lacks the RER connection of Lyon and may not have enough space for all the TGVs. A connection pointed towards Gare du Lyon would need two new overpasses instead of one, and it might not be possible to connect trains heading towards Gare du Lyon to the ceinture because the Bd Poniatowski is in the way.

        • Matthew Hutton

          Wouldn’t this be the cheaper option? Buy new trains that can be unloaded as fast as the Shinkansen and then have a cross platform interchange for the trains to the north, east and south?

      • Mikel

        Thanks for the reply; speaking as someone whose rail connection to much of Europe is via the LGV Atlantique, the idea of a one-seat ride from Hendaye to London and Amsterdam (or at worst a cross-platform transfer at the new underground station) seems very interesting. However, given the Macron administration’s feet-dragging on international connections, dou you think such a project has a chance of being considered in the next 10 years?

        Pehaps (scope creep!) this could be bundled with your proposed deinterlining of the RER B/D. A large-diameter tunnel from Montparnasse could carry TGVs on one pair of tracks and the RER D on another, and with bi-current EMUs you could interline the Transilien H and N with the RER D on the local tracks, creating a new north-south RER trunk. This could require rebuilding some of the junctions at the north side of Chatelet-Les Halles, which I’m not familiar with. OTOH the extra capacity on the RER B would allow for more service to the airport and thus save money by making M17 redundant.

          • Mikel

            Yes, there’s a pretty ambitious RER crayon here, and a brief mention to the TGV tunnels in the Eurail post, but I don’t think they’ve ever crayoned a combined RER/TGV proposal?

  6. SB

    Is there much of demand for additional regional/intercity line between Hamburg-Altona in the first place?
    After the construction of Fehmarn Belt Fixed Link, the biggest city north from Altona is Kiel which isn’t that big.
    Or the line mostly for through running to Altona?

  7. Frederick

    On a related note, currently there are 9 tph through Blackfriars bridge on each direction. Is there any reason why the bridge can’t run 24 tph?

    • fjod

      Where are you getting that figure from? There are 14tph at the moment, down from 16tph pre-pandemic (the Kentish Town [peak Luton] to Orpington stoppers have disappeared). Frankly the reason they’re not running more is that there’s no demand for it at the moment, given a) the huge capacity of each Thameslink train and b) the particularly strong bottoming-out of the city commuter market who fill trains from far-flung (hence high-fare) places like St Albans and Sevenoaks.

      • Borners

        Its also because they’ve screwed up infill in those places; Peterborough alone could probably use 4-5 more stations alone. As a result they don’t have local trains acting as feeders for Thameslink as well as they could (this is what happens in Japan with Kansai and Aichi’s comparable cross-city services). This is less of a problem South of the river because Southern railways before nationalisation actually understood how to build electric railways properly. Unlike BNR or contemporary UK operators. Honorable exception for Cambridge but that’s because the LA is Yimby.

    • TheKorot

      The bridge very much is designed to do 24tph; as is the rest of the Thameslink core.
      Unfortunately, when the time table to start running 24tph was introduced things went very wrong and service was reduced to 16 (or 18) tph until a method was found to get 24tph reliably. And then Covid reduced it somewhat; but should go back to pre-covid eventually. And then presumably cut branches at the south side to reduce delays screwing up core entry.

      • Borners

        I fear nobody in power understands how unnecessarily snarly the interlining is for the South London rail lines. Thameslink is the worst though. That Wimbledon loop is terrible especially given the relatively little overcrowding there is on the district.
        I mean compared to Meitetsu Nagoya station’s 26 tph with way less track/platforms, 5 times as many users despite not being in the CBD and smaller train cars. Its pathetic.

        • TheKorot

          The Thameslink core stations are all 2 platforms though, not sure how you want to run more tph on fewer than 2 tracks/platforms. They all also have other platforms for other services, but those don’t count towards the 24tph figure I gave above.

          • Frederick

            Meitetsu Nagoya is also double track only. Heck, even RER A is double track only. So it’s definitely possible to run a higher frequency.

            Thameslink, unlike Meitetsu Nagoya line or RER A, also runs regional trains. Anything lower than 24 tph is a shameful underuse of infrastructure.

  8. fjod

    TfL get it, at least to a degree, though seemingly they think the peak doesn’t count (p66 current vs p57 proposed):
    Even better if the Hayes line becomes Bakerloo too – then that interlining goes away too.

    The trouble is that for the last twenty – and especially the last five – years, the services have been run by companies who have no incentive or legal power to carry out long term investment and make difficult decisions to enable deinterlining to happen.

    • Frederick

      The first step should be making TfL the only organisation responsible for all London commuter trains (and fare-integrate them with other TfL services). It’d be even better if TfL actually owns the infrastructure.

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