The capital cost of providing sidings, yards, stations and depots is just as firmly fixed as the cost of providing route, but the cost of operating these facilities does vary to some extent with the level of traffic using them. Even so, the extent of this variation is small, especially on a short term basis, and a large part of shunting and terminal costs must be regarded as fixed, all the while the associated route system remains unchanged, or until stations are actually closed, or closed to some forms of traffic.
It is these considerations which make so interesting the information derived from the traffic density surveys, the results of which are presented more fully in Appendix 1. In what immediately follows, reference is made only to salient features, but further references are made in subsequent sections, where we return to considerations of various classes of traffic.
The traffic surveys, which were made in great detail, extended over only one week, the week ending on 23rd April, 1961, because it was impossible to continue the massive recording effort involved for a longer period. It was realised, therefore, that conclusions about some streams of traffic and about some parts of the system which are affected by seasonal changes could not be based firmly on the traffic surveys alone. Subject to this limitation, however, there can be little doubt about the general reliability of the picture revealed.
The tables and graphs in Appendix 1 show how pronounced is the disparity in loading between heavily loaded and lightly loaded parts of the route system. One third of the route mileage carries only 1 per cent. of the total passenger miles. Similarly, one third of the mileage carries only 1 per cent, of the freight ton miles of British Railways. The lightly used part of the system includes most of the single track branch line, of which there are 5,900 miles and of which 2,700 miles are open to freight traffic only. The proportion of British Railways' total, passenger and freight revenue corresponding with this proportion of total traffic movement is £4½ m., while the cost of providing this route is some £20 m.
One half of the total route mileage carries about 4 per cent. of the total passenger miles. Similarly, one half of the mileage carries about 5 per cent. of the total freight ton miles of British Railways. The corresponding apportionment of total passenger and freight revenue is S20 m., and the estimated cost of providing this part of the track is of the order of £40 m. Therefore, in so far as it is reasonable to judge earnings in terms of the traffic movement provided, one half of the system earns far less than sufficient to cover the cost of providing route to permit the movement, with no allowance whatever for movement or other costs. By contrast, the other half of the system has earnings which cover its. route costs more than six times.
It is recognised that the foregoing basis of consideration does not take account of the actual nature of the traffics on lightly loaded lines, of any special cost and charging feature associated with these traffics, nor of any contributory value which they may have to the remainder of the system. These matters will be considered later, however, and it will be found that so far from being exceptionally good traffics, most of the traffics fed to the rest of the system are of the less favourable kinds, and that their contribution of marginal revenue is small if not negative.
The disparities in the flow of traffics through stations are even more pronounced than those found in relation to routes. This is not surprising, because apart from the large variation in the size of the stations themselves, many of the smaller ones are on routes which are also lightly loaded.
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