tisdag 26 augusti 2008

High Speed Train replacement saga continues

Originally uploaded by Ingy The Wingy

This project is another one the Department of Transport and the consultants have got into a deeper and deeper mess with. So far, nearly £10 million have been spend in consultancy fees, and at the end it is likely to end up at about £15 million and still not deliver anything that fully meets the specification and could not have been bought virtually off-the-shelf.

The problem is that the Department of Transport has got up a concept for a train that can be almost everything at once. They want light weight, to save energy, 140 mph capability and the ability to operate both with electric power and under some other form of power when running on lines that are not electrified. And very high reliability.

Light weight on its own should not be too difficult to achieve. Adopt an efficient form of construction for the body shell and pay attention to the weight of components such as seats, which can add up. Constructional systems such as the mark 3 have proved more than adequate in most situations and it may be that crashworthiness requirements need to be re-thought. There are other constructional systems for bodyshells which may deliver what is needed; stainless steel with corrugated panels has been widely used though not in Britain. Seats have got heavy in recent years but that is partly due to the adoption of airline style configurations, which mean that each seat requires a sturdy frame. If seats are arranged in a back-to-back configuration, the seats together can be made to form a substantial structural unit, and, incidentally provide luggage space between the adjacent seat backs, the lack of which has become a widespread source of dissatisfaction.

140 mph capability is another matter. It probably is not needed. With the rising costs of fuel, the competition from low cost airlines and cars is going to be of diminishing importance. The costs of speed are high. An object moving at 140 mph contains twice the kinetic energy of one going at 100 mph. Air resistance increases at a rate of more than the square of the speed, and there are other costs associated with higher speeds such as the need for more sophisticated suspension, signalling and braking systems, better crashworthiness, and added wear and tear on both track and mechanical components on the trains. In a country with a population distributed as it is in Britain, with 85% of people packed into one-third of the land area, the benefits of very high speed rail travel are nowhere like what they are in France, with its large cities and areas of empty space between. Britain’s railways need to provide good coverage and journey opportunities, which mean having stations relatively close together and trains having high capacity and good acceleration. The only possible routes where TGV-style services might be justified are London to Newcastle, Edinburgh and Glasgow.

What of the ability to operate with different kinds of power? The obvious answer is to use a separate traction unit, usually known as a locomotive, which does not necessarily need to be at the front end of the train and can equally well be at the rear. But if one examines the precise routes where the new trains would be running, the entire multi-mode requirement comes into question.

The two routes concerned are the East Coast and Great Western main lines. The former is electrified between London and Edinburgh, and the likelihood is that the independent Scottish authority will give the go-ahead for electrification between Edinburgh and Aberdeen. So on this route there should be no need for a train that is both diesel and electrically powered. And if a new line of TGV standard is eventually built, then the need will be for standard TGV-style trains to run on it.

The Great Western is another matter. London to Bristol and Cardiff has turned into a commuter route with frequent stops, where the need is for frequent trains with high capacity and good acceleration. Much like the Southern routes, in fact, where a train such as the class 444 suits the requirements perfectly well. Electrification from London to Bristol and Cardiff is overdue; the important junction at Reading, 36 miles out of London, must be one of the busiest non-electrified stations in Europe. Electrification to Reading is now agreed as part of Crossrail (if it happens), and there can be no justification for persisting with diesel traction as far as Bristol and Cardiff.

Beyond that, the case for electrification is weaker, due to the lower volumes of traffic, except perhaps to Newbury and possibly Exeter. But the latter town is also on the line from London via Salisbury, another destination which, sooner or later, is likely to see electric traction extended there from Basingstoke. So it might be more worth while to electrify to Exeter via Salisbury, using a route which serves a number of medium-sized towns on the way, unlike the Great Western route through Westbury. In that case, the best way to run the route beyond Exeter (where a reversal takes place in any case due to the track layout) would be on the same principle that the London to Weymouth services operated when electrification went only as far as Bournemouth; the electrically powered half of the train was split off and the trailer cars were worked on to Weymouth using diesel locomotives in push-pull mode. The same method could also be used for trains on the Great Western main line running beyond Bristol if electrification was only taken that far.

Details aside, this demonstrates that if electrification schemes that were long overdue were actually carried out, the requirement for the Department of Transport’s high speed dual-mode train disappears.

There are other issues on top of this. The Department of Transport is talking about the need to save energy. A train contains an enormous amount of embodied energy – that is, the energy used to dig the raw materials out of the ground and convert them into steel and the other metals used for construction. It therefore makes sense to keep the hardware in service for as long as possible. Experience suggests that monocoque steel railway vehicles should have an economic life of around sixty years. Mark 3 stock, built between 1970 and 1985, is not showing signs of serious corrosion and should therefore be expected to last until from 2030 to 2045. On the same basis, Mark 4 stock (photograph) should be able to continue until into the 2050s, and the same could be true of the class 91 locomotives that power the East Coast Main Line trains. So what is the DoT even thinking about when discussing replacements for these train in the period up to 2020?

Beyond that, there is the possibility of the construction of one or more high speed lines in Britain. As suggested earlier, apart from the exceptions mentioned earlier, the need for high speed in Britain is questionable, but the need for new lines to provide additional capacity is not. Whatever form these new lines will take, it is inconceivable that they will not be built to full European standards; in fact, they will have to be to enable non-dedicated European trains to use them. So these routes will indeed need a special fleet of trains, though they may in practice, and ought to be, a standard off-the-peg design such as the Alstom TGV replacement.

However the matter is looked at, the Department of Transport is just throwing money away on consultancy fees with this project. It does not make sense in any terms.

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