söndag 9 november 2014

Two into five won't go



Railways approach Göteborg from five different directions. Starting from the twelve o'clock position, these are Strömstad-Uddevalla, Trollhattan-Älvängen, Stockholm-Alingsås, Borås and Copenhagen-Kungsbacka. There is no route across the city which has a significantly greater traffic potential than any other, and the connect must necessarily be arbitrary. Whichever lines are joined by a cross-city link, most journeys through the city centre will inevitably require a change just as they do now. If services from the two lines from the north continue onto the one line from the south, the result will be that the southern line will be unnecessarily congested and the potential traffic will be insufficient for the service provided. Or half the trains will have to turn round and go back.

A further drawback is that passengers travelling to and from the south to the city centre and northwards will actually experience longer journey times due to the detour they will now be making through having to make a trip all the way round the city centre through the expensively constructed tunnels.

In these circumstances, there is only thing to be gained from constructing a cross city link, is the reduction in the number of trains terminating at the central station, and the associated costs of platform occupation and train movements.

Against that is the disadvantage of joining separate networks: that delays and disruption are propagated from one network to another. A failure at, say, Alingsås will lead to cancellations at Kungsbacka an hour or so later. This was precisely the experience with London Thameslink, a long-distance cross-city route.

Diminishing returns of British high speed rail

The typical inter-city journey in Britain is about 100 miles. Now look at this table of speeds and journey times; remember that to achieve a...