beleben

die belebende Bedenkung

New-build versus “Victorian infrastructure”

with 14 comments

One of the arguments for new-build HS2 is the so-called “step change in capacity” it would provide compared to “Victorian infrastructure”.

But as can be seen from Figure 1.2 of the Government Response to the House of Lords Economic Affairs Committee report, path capacity on the “Victorian” West Coast fast lines exceeds that of new build high speed lines, such as the 1980s Paris Lyon LGV.

Clearly, “Victorian infrastructure” can be resignalled to provide similar headways to new-build lines.

So, one of the numerous options for increasing capacity on the West Coast corridor would be to resignal the southern part of the route. A 150-second-headway (which would not require moving block) could provide at least 18 fast paths per hour.

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Written by beleben

July 3, 2015 at 11:57 am

Posted in HS2

14 Responses

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  1. Surely what the table shows you is how many trains per hour are being operated on each of those lines. It doesn’t tell you what the maximum theoretical capacity of each line actually is. So another way of interpreting it is that the West Coast Main Line is being worked more intensively than comparable Continental lines.
    The technical headway at the southern end of the WCML is (in most cases) between 90 and 120 seconds already, following the West Coast Route Modernisation completed in 2008 (or thereabouts). So resignalling would not be necessary. However increasing the number of trains per hour could only be done my stripping out more stops at Watford Junction and Milton Keynes Central, and banishing the LM Fast services (110 mph) to the Slow Lines. It’s easy to run more trains if they all have identical stopping patterns and speeds, but social and commercial requirements to meet passenger demand at Watford and Milton Keynes prevent that from ever happening.

    Jeff Hawken

    July 5, 2015 at 8:20 pm

    • The table doesn’t give a complete picture, and rail capacity is complicated. But the possibility that more trains could run on existing lines by homogenisation and redistribution of traffic, is worth investigating. On the West Coast Fast, the capacity pressure is mainly London — Milton Keynes (rather than London — Rugby) and the problem is not so much ‘stopping’ trains at MK, as ‘re-starting’ them in a situation where most trains pass through without stopping.

      beleben

      July 6, 2015 at 9:20 pm

      • With the current signalling on the southern end of the WCML it is theoretically possible to equal the 18 homogenous train paths per hour proposed by HS2 (provided of course that you have a Euston station with sufficient platforms to send that many trains hour after hour, but that’s another question). However when a train diverges from the homogenous 125mph non-stop standard path, it can cost you another path.

        Off-peak, there are currently 9 Virgin trains per hour out of Euston (3 West Midlands, 3 Manchester, 1 Liverpool, 1 Chester, 1 Glasgow). So that’s 9 of your 18 paths used.

        Four of these trains call at either Watford Junction (1) or Milton Keynes Central (3).

        In addition, there are three London Midland services running at 110 mph, which between them also consume about 5 paths because of their slower running and stopping pattern.

        So that gets you to around 18 paths consumed pretty quickly.

        Now because of some clever timetabling, there is some double-counting in the above figures, but the pain really comes on in peak hours when additional peak-hours fast line services need to run. The WCML Fast Lines are running very close to their maximum capacity at this point.

        I conclude that increasing the number of trains running on the southern end of the WCML would come at the expense of reducing or eliminating stops at Watford Junction and Milton Keynes. It’s not really a palatable solution, especially given the growth in traffic from MK in recent years.

        Jeff Hawken

        July 6, 2015 at 10:35 pm

      • Certainly, there is a degree of tradeoff as far as Watford and Milton Keynes are involved, but there is no figure for the monetary worth of intercity trains stopping at those places.

        Those towns’ rail travel is going to be mostly to and from London, and there is almost no information about what demand might be between Manchester and Bletchley (etc).

        This blog has put the case for eliminating all intercity stops at Watford Junction, and all “through” intercity stops at Milton Keynes. It’s by no means clear why the city of Milton Keynes has to have four peak hour commuter fast trains into Euston (rather than say, St Pancras Thameslink).

        beleben

        July 7, 2015 at 9:17 pm

      • Watford Junction has already lost all but one of its Inter City services per hour. Eliminating its last remaining express service might save one path per hour.

        Milton Keynes is an area experiencing rapid growth. The remodelling of the station in 2008 is testament to that. From personal observation, as a fairly frequent user of the WCML there are always a good number of passengers getting on and off in the off-peak hours. During the peaks the fast trains tend not to stop there – partly for train timetabling and partly because they would be overwhelmed.

        Milton Keynes is pretty much equivalent to Reading on the Great Western. They are similar sized conurbations both about 30 minutes from their respective London Termini, and yet Reading sees a far greater proportion of trains stopping than does MK. Arguably MK is under-served by long distance services at the moment.

        Jeff Hawken

        July 7, 2015 at 10:21 pm

  2. One wonders what the overall capacity would be on the WCML if either it were run as one “fast” four track railway, rather than what appears to be two two-track railways, one “fast” the other “slow”. Also if the tracks were paired by direction rather than by “speed” trains could more easily overtake,

    strawbrick

    July 6, 2015 at 10:13 pm

    • Having a “fast” four track railway would have certain operational advantages when things go wrong, or at times of maintenance closure, but would do little or nothing to increase the overall route capacity. In fact the opposite may apply. The reason is that you have a wide range of stopping patterns and maximum train speeds. So separating the trains into “fast” and “slow” actually helps maximize your capacity benefits, whereas interweaving fast, semi-fast and slow passenger services alongside freights on two equal-speeded tracks would make things worse.

      If one pair of lines was greatly under-utilized and the other full to capacity then there would be some merit in examining this further, but that is not the case here.

      Pairing by direction rather than pairing by speed makes transfer between lines in the same direction considerably simpler, but it’s not as big a benefit as you might think. Consider a train running at 125mph overtaking one running at 75mph. Even with perfectly-placed crossovers, if both trains are to see green signals throughout the process, it would take nearly 20 miles for the overtake manoeuvre to be completed.

      Jeff Hawken

      July 6, 2015 at 10:54 pm

      • One problem is the running of freight trains at up to 75mph on the slow lines. The current utiisation on the slow lines is far below that of the fast lines with some of the freight paths being unused.

        Two solutions would be:-

        1) Divert more of the freight trains away from the west coast slow lines- potentially via re-openings and gauge enhancements of other lines.
        2) Use passing loops at stations on the slow lines – so stopping LM trains can be passed by fast LM trains (both using the slow lines) – e.g. at Tring, Bletchley or Milton-Keynes

        The west coast fast lines could then be used by only 125mph trains

        richie40

        July 7, 2015 at 10:53 am

    • The freight trains would need to be diverted away from the slow lines.

      Gauge enhancement may be required on other lines. Recent Network Rail projects to do this appear to cost an order of magnitude of £1mn/mile.

      Re-openings may also be required – e.g. Northampton – Bedford to enable the Midland Main line to be used or Calvert – Rugby to enable one of the Chiltern lines to be used. The order of magnitude for the cost of re-openings is around £10mn/mile.

      The “estimated” cost of HS2 is around £200mn/mile.

      richie40

      July 7, 2015 at 11:04 am

      • This seems to me to be simply moving the problem, rather than solving it. Once Thameslink is open fully, there will not be much capacity to spare south of Bedford on the Midland Main Line. Likewise the southern end of the Chiltern Line is also pretty full, and Chiltern Railways are investing more to cope with passenger growth.

        Don’t forget that the Calvert to Rugby line never actually connected with the West Coast Main Line at Rugby, it went over it at right angles. So considerable reconstruction would be needed in the centre of Rugby in order to make this connection. Reopening old railways in order to move freight to places it neither needs to be nor can easily be accommodated is not a viable alternative to anything.

        Jeff Hawken

        July 7, 2015 at 4:20 pm

      • The capacity potential of the Chiltern and Midland routes does not seem to have been examined in much detail, and the “no capacity” folklore is not convincing.

        Apparently, as part of the Thameslink Programme, some trains from Blackfriars are to be routed away from the Midland (making it ‘less busy’), and onto the Great Northern. But one could imagine alternative scenarios in which all or virtually all Thameslink trains continued to run on the Midland, to destinations such as Bletchley, Corby, and Northampton.

        If the Chiltern route is “full” now, neither the future Evergreen 3 to Oxford, nor the East West Rail from High Wycombe to Bletchley, could operate.

        A GC / LNWR connection in the centre of Rugby would be awkward, because of the angles involved. It would be possible to a provide a better connection east or west of the town centre.

        beleben

        July 7, 2015 at 8:52 pm

      • On the Midland Main Line, freight operators already find it difficult to obtain additional daytime paths, because of the density of the slow lines passenger services, and the platform occupation at Bedford. The construction of new lines north of Kings Cross / St Pancras will allow some Thameslink services to connect onto the Great Northern route, but the number of trains through Thameslink will increase to a maximum of 24 tph. So the Midland Main Line doesn’t get significantly less busy than now. The eventual electrification of the route north of Bedford (scandalously postponed just recently, alas) would see any remain capacity mopped up by improved services to St Pancras, and possible future extension of Thameslink services north of Bedford – as you note.

        I took the Chiltern future expansion – including Oxford – into account with my comments. High Wycombe – Aylesbury – Bletchley does not affect the core route.

        Any connection at Rugby would need to be south of the station – ideally in the vicinity of Hillmorton Junction – so as to provide route options towards either Birmingham or the Trent Valley.

        Jeff Hawken

        July 7, 2015 at 10:10 pm

      • Instead of using the Midland main line for the diverted freight trains, Bedford – Hitchen could also be re-opened, along with the link between the two Hertford stations and a new line built alongside the existing West Anglia line.

        richie40

        July 7, 2015 at 11:09 pm

  3. For info, the Thameslink 2018 timetable proposals can best be seen on this Wikipedia page:
    https://en.wikipedia.org/wiki/Thameslink_Programme
    Scroll down to the section “Provisional Timetable”. The numbers 1 – 24 in the left hand column indicate the trains in each hour.

    Jeff Hawken

    July 7, 2015 at 10:31 pm


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