High Speed 2 (HS2) is the new railway line currently under construction that should run from London to Birmingham and then on to Leeds (via the East Midlands and Sheffield) and Manchester, with connections to the classic network so trains can run beyond there. Always controversial, a significant amount of media coverage in recent months has meant that public opinion has very much turned against the rail project. This is the first of two articles which cover the current situation with HS2. Part 1 focuses on the case for HS2: the problems that exist now and why HS2 actually solves them.
Against popular belief, the main focus of HS2 is not to decrease journey times between cities, but to increase railway capacity on some of the most congested parts of the UK's railways: the West Coast Main Line (WCML) and branches of it. Specifically: the southern section from London Euston to Hanslope Junction; the Coventry to Birmingham section; Birmingham New Street station; Crewe station and the junctions around Crewe; the Manchester branches of the WCML; the Stockport to Manchester throat; Leeds station and others which aren't quite as major, but will most likely become more problematic as capacity is swallowed up by continued demand.
Those Capacity Constraints in Detail: Southern WCML
The Southern part of the WCML is at capacity. By that I mean that no additional trains can run at the busiest times of day (AM and PM peak) without significantly slowing down faster services. The problem with this section of the WCML (and indeed the line as a whole) is that there are a lot of trains which run at a lot of different speeds. On the passenger aspect, there are 3 maximum speeds at which trains can run: 100mph, 110mph and 125mph. One then has to add the freight which generally runs at either 75mph or 60mph. Some run much slower (down to 45 or 30), but these are rare and run at night because one simply can't run such slow trains during the day on such a busy railway line, so will be ignored for the purposes of this article. The maximum speeds aren't the only consideration: different trains have different acceleration/braking profiles and platform dwell times (rate of change of speed and how long they must spend at a platform), but I will ignore these for simplicity.
The moment one has different trains running at different speeds, the timetable has to compromise on either speed or capacity. IE: The faster trains must slow down to the slower speed, or the faster trains have to depart 2 or 3 paths (a path being a space in the timetable where a train can depart) later so that they don't catch up with the slower train instantly. That, of course, reduces the total number of trains one can run.
The way HS2 solves this capacity problem is by removing the faster (125mph max) services from the WCML, meaning that there are fewer different types that run which means that capacity is used more efficiently. On the fast lines of the WCML, once one removes the 125mph max services, 110mph is the only speed that one has to worry about, which means (in theory), one can have a train running in every path out of Euston. (The difference in stopping patterns may mean that not every single path is used, but significantly more trains will be able to run.) One can provide additional services to under-served commuter towns, and provide quicker services to places such as Northampton which simply can't have an adequate service without HS2 because of these capacity constraints.
Coventry to Birmingham/Stoke-on-Trent to Manchester
This one is fairly simple. The railway between the two cities is only double track which is inadequate to serve the different traffic that is required: InterCity services (which only stop at one or two stations between the cities), and local stopping services, which should stop at every station between the two. The mixture of fast and stopping traffic means that the stations that aren't Birmingham International or Macclesfield don't get a reasonable service, and stopping patterns for the stopping trains have to be spread across different trains. IE: instead of one train calling at all stations, there are three trains stopping each at a third of the stations. For Congleton, the situation is much worse: an annual patronage of about 300,000 is served by one train per hour, which is a huge mismatch in demand. This does nothing for interconnectivity between the stations, and means that most don't get enough trains per hour. By removing most of the InterCity services, capacity is significantly increased, in much the same way that capacity on the Southern WCML can be increased: significantly more trains.
Station Specific Capacity Issues
I mentioned Birmingham New Street, Crewe and Leeds specifically at the top of the page, but they all really have roughly the same capacity problems: too many trains, too few platforms, not much space to expand. A current solution at Birmingham New Street has been to “combine” services. A Rugeley Trent Valley to Birmingham and Birmingham to London train becomes a straight through Rugeley to London service. This has both upsides and downsides: Upside – more capacity through Birmingham New Street, more direct services between places. Downsides – a problem on any part of that long route will transfer much faster to other parts of the network, and new parts of the network. (EDIT (Oct 2019): I explored the specific issue with these through Birmingham services in an article published in September. Click here for said article.)
Take the ThamesLink example: now that ThamesLink is fully built, a problem in Brighton will end up affecting services as far north as Inverness. Trains now run from Brighton to Cambridge, which means that any delay they pick up will affect other trains on the East Coast Main Line (ECML), a route which has very few gaps in its timetable. That Brighton to Cambridge service arrives onto the ECML late, which means it has lost its path. So, it effectively takes another train's path. Given that the ECML is also used by a lot of InterCity services to Leeds and Edinburgh, the delays to those get transmitted through any other bottleneck (and there are a lot of them en-route). So, that problem in Brighton has cause disruption to numerous passengers across the whole country.
Through services aren't a bad thing, but they do create much more risk. By taking out the 3 InterCity services per hour that terminate at New Street from London, there will be capacity for more than 3 more local services to terminate. I'll explain: InterCity trains require longer turnaround times at termini for un-loading, cleaning and preparation, and re-loading. Local services can turnaround in the minimum specified by the timetabling rules, mainly to do with the length of a train. 2 car branch line services can turnaround in a minimum of 3 minutes, for example. It would be impossible to turnaround an InterCity service anywhere close to that time, or even the minimum for the longer trains that use Birmingham New Street.
Leeds has too many trains terminating, which means that trains have to be stacked up on platforms. This works in normal times, but the moment one train becomes late, or misses it's platform slot, signallers can quickly run out of platforms, leaving trains sitting outside the station. HS2 won't solve all of this, but it will remove some of the terminating long distance services, which always helps.
Below is a map of Crewe and the surrounding tracks. Clearly, there is a serious amount of complexity, not enough platforms and not enough capacity. HS2 will take the services which currently don't stop at Crewe, but still eat up capacity through the station. It will also expand the station as Crewe becomes a larger interchange station between HS2 and “classic” services.
The Manchester to Stockport Throat
The problems with capacity on this line could be put down to “too many trains, too few paths”, but this is a slight simplification. Whilst there are a lot of trains which need to use this piece of track, the paths are used very poorly, and not due to the normal reason of different speeds or stopping pattern.
InterCity services between London and Manchester currently operate every 20 minutes (3 trains per hour). This is against the normal frequency of services, which is every 30 minutes (2 trains per hour) or every hour. Thus, the timetable has to go from one where trains run at the same point every half-hour, to one where they run at the same point every hour, which gives uneven frequencies on some routes. It also means that some services can't run every half-hour because their path is used up at the opposite time by an InterCity service.
See the current situation on the Mid Cheshire line which runs from Stockport to Manchester: A franchise obligation was to increase the frequency on this route to 2tph, but there is simply not the space to run these services beyond Stockport. Thus, the second train per hour now terminates well south of Central Manchester, leaving passengers with an inadequate service.
The problem is compounded by the serious capacity issues on the approach to Manchester Piccadilly, and the serious lack of platform capacity there. Despite some trains being diverted away from Piccadilly to Manchester Victoria, neither has many spare paths or platforms at any point.
Things Which Don't Work
Although most opponents of HS2 don't tend to offer any replacements which solve the problems, some do. This is the debunking section:
More tracks on the current alignment:
There simply isn't the space. 6 tracking the Southern WCML, 4 tracking Coventry to Birmingham and Stoke to Manchester would be very expensive, would demolish a lot of houses (more than HS2) , and wouldn't provide all the benefits of HS2 (faster journey times, as much new capacity, and the station capacity problems).
Adding more carriages:
Either because the train is already at maximum length, or because it will only address demand for the short term.
Long distance trains on the WCML come in 5, 9 or 11 coach formations. An increase from 5 to 10 coaches is a doubling in capacity, but trains already run doubled up at peak times. Adding 2 coaches to increase the length of the train up to 11 is a very small increase, and will therefore be full in a few years. The situation with shorter distance services is broadly similar too: even the biggest increase possible in peak time (from 8 to 12 coaches ) will mean that trains which are currently absolutely rammed become mildly uncomfortable for a few years, before they fill up again with new passengers.
Even extending trains beyond the current maximum length poses problems. Firstly, one would have to extend the platforms of most stations. This simply isn't possible in a lot of cases. Secondly, it would still only provide finite capacity which would be used up in the medium term (say 5-10 years). It is a typical example of political “can kicking” where people attempt to put off making a decision or doing something radical for the next few years. Another example is banning plastic straws to prevent climate change, whilst doing nothing about big oil.
The Overall Case
Simply, the railway line would separate fast InterCity services from more local and commuter services, and thus create a significant amount of new railway capacity around Birmingham, Manchester, London, Crewe and others. This means that a lot of areas which won't be directly served by HS2 will see their rail service improve significantly because the paths would exist to give them the service required. Other proposals don't solve or do as much as HS2 will, if it is built fully.
(The reason for it being High Speed? Well, it will only be used by InterCity services which make few stops, so one might as well make journey times quicker between cities.)
In Part 2 I explore the failures of PR from the government, the dishonesty of the media, and the possible consequences. Click here.