The high speed train (HST) is a technological advance in passenger transport which has allowed to increase the railway's share in modal split in medium range distances, competing with road and air transport. In this article a conventional cost-benefit analysis is carried out from demand and cost data available and under several assumptions about the life of the project, growth hypothesis, time and accident values and with a social discount value of 6 per cent in real terms. The social evaluation of the project shows that the Spanish HST should have not been carried out in 1987 and in the chosen corridor. The actual pricing policy of RENFE appears compatible with first economic principles as infraestructure costs are sunk and the existence of peak periods and budget constraints justify the price structure of the company.

Keywords: infrastructures, cost-benefit analysis, transport, public ex-penditure, railways, high speed train.