Why HS2 Being a Bit Slower Isn’t Much of a Problem


Dear reader, this article (or at least the first two thirds of it) was intended for another publication, so the tone may be slightly different to what you have come to expect, but in any case, I thought it a shame to waste it, and that the point warranted bringing to your attention.

Headlines were made when, recently, the Chief Executive of HS2 Ltd, Mark Thurston, announced in a meeting with MPs that changes may have to be made to the project to bring it in within budget and on time. These changes include reducing the speed of the trains and reducing their frequency. Suffice to say, these changes caused something of a stir, with comments in the newspapers (notably the Metro) questioning the point of the project.

In answer to this entirely ill-informed outrage, let us take a reality check. Firstly, we shall deal with speed. It is well publicised that the top speed of the line may be reduced by 30 mph. It seems that those outraged by this supposedly huge reduction could not be bothered to do some very basic arithmetic, since the very same articles that said this also said that the original intended top speed was 225 mph. The top speed would then be 195 mph, which isn’t exactly slow – that’s still 70 mph faster than the 125 mph top speed on the current London – Birmingham route.

If I may be allowed to speculate, this may not even impact the journey time very much, mainly because of aerodynamics. As should be obvious to anyone who’s ever ridden a bicycle or driven a car, as an object gets faster, the resistance from the air increases. The trouble is, it is not a simple relationship – it is not the case that doubling the speed doubles the air resistance. In reality, if you double the speed, the air resistance quadruples. At the top end of the speeds of HS2 trains, this means the acceleration will be quite slow, so they likely would not spend much time at 225 mph anyway.

Secondly, we must address the point of train frequency. The train frequency may be reduced from 18 trains per hour to 14 trains per hour, or 7 in each direction per hour. Quite aside from the fact that this still means a train roughly every eight and a half minutes, this should not be a news story at all. Or rather it should have been several years ago. As early as January 2012, the HS2’s review of the technical specification had this to say on the subject: ‘A number of consultation responses expressed the view that achieving an ultimate capacity of 18 train paths per hour… was not feasible, citing international experience where no high speed rail lines currently achieve this’. Needless to say, the recent news should not have come as a surprise.

No, the part of the recent news we should actually be concerned about is the less obvious point; to quote the Evening Standard “changing from a slab to a ballast track”. Without going too far into the technical details, this means changing from a newer system which requires little maintenance (if installed correctly) to a much more conventional one that, while cheap to lay, requires considerable maintenance over the life-cycle. In other words, we would pay less now but more later, so much so that the overall cost may well be much higher.

There really isn’t much else that can be said about this, but in traditional Peculiarly Pete fashion I shall continue. I shall do this by reiterating that the only realistic way to solve the capacity problems of the West Coast Mainline (that’s London to Birmingham, Manchester, Liverpool and Glasgow) is to build another line. One cannot really widen the existing route without disturbing a great deal more property than HS2 will. One equally cannot extend trains by enough to make much of a difference, especially as far as Virgin trains are concerned, where the limitation is platform length (true, one could extend trains further, but they would spend longer in the platforms, especially with the rather narrow doors required for inter-city trains).

Besides, extending the passenger trains either does nothing for, or negatively affects, the freight operators who use the route, who would also benefit from the extra capacity. Longer passenger trains also take longer to clear junctions and put more wear on the track, leading to more maintenance work, often at times that are inconvenient for freight. Let us not forget the environmental advantages of railfreight – why use 30+ lorries when 1 locomotive can do the same job? (obviously there are convenience advantages to lorries, but over the long haul these diminish in importance).

In any case, thank you for reading this slight mongrel of an article. Once again I would advise changing here for any of the other splendid articles on this website, and ask you to retain your tickets for the automatic barriers, and other associated end-of-journey-announcement cliches.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s