A previous posting was criticised on the grounds that a Network Rail study found that revenues increase much faster than costs as speed increases, and also that benefit/cost ratios rise with speed. Pages 27-30 of the Network Rail New Lines Study were referred to.
The difficulty is that the conclusions drawn in these documents tend to be quoted without a thorough study of them. The Network Rail New Lines Study would take several days of careful reading in order to make a proper critique. In fact, it would take nearly as much work as was needed to produce the original report. Who has done this? Who has the time and other resources to do this? The consultants who wrote the report, Steer Davies Gleave are amongst the leading advocates of High Speed Rail, being also the authors of the Greengauge21 report. It is natural that they are going to present it in the most favourable light possible.
Any such study involves making many assumptions about the future and about people's behaviour. These may be wrong and events may turn out differently. There are also questions to be raised about the general methodology, in particular over how external benefits are measured. This might look like hard science but it is not. There is also, it has to be said, plenty of valuable business to be obtained by consultants and construction companies if the project goes ahead, so this is not advice from disinterested parties. There are no disinterested parties when a matter like this is concerned, since all options produce losses and gains for someone.
One point that is clear, however, is that it is assumed that premium fares will be charged for travel on the high speed line, which puts a different complexion on the whole project, does it not?