STRAITS OF GIBRALTAR

Hokitika Guardian, 5 April 1929, Page 5

STRAITS OF GIBRALTAR

DIFFICULTIES OF TUNNELLING

"Will the Straits of Gibraltar be tunnelled before the English Channel? “ Modern Transport ” gives the following answer:—“ Although great reserve is being maintained b t v the commission which is investigating the possibilities of a tunnel under the Straits erf Gibraltar, there are, according to a messagel received in London, good prospects of an actual beginning being made with the work in the near future. The main idea of the promoters is that the tunnel should form part of a direct through service that would connect Paris with a network of railways In Africa, having Tangier as its converging point. In view of the revival of interest in the Channel tunnel project, it is natural to make some comparison between the two schemes. From an engineering point o'l view, the Gibraltar project presents the greater difficulties, since the tunnel would have to he driven through rock instead of clay. “Another difficulty arises Iroin the fact that the Straits of Gibraltar are considerably deeper than the Channel, and the tunnel would have to he laid at least 1000 feet below sea level, whereas in tlie* case of the Channel tunnel the depth is estimated at less than 250 feet. The route which will almost certainly be selected lor the Gibraltar tunnel is the one now being examined by the commission. This is known as the Tarifa-Tangier route. It would involve the construction of a. tunnel some 30 miles long.

“The actual length of the under-sea portion would not exceed 20 miles, but a long approach on the Spanish side is necessitated by the If act that the Straits at this point reach a depth of about 1300 feet. The route is, however, considered favourably in Spain, because it would enable an easy connection to be made with the existing railway which terminates at Algeciras. “ According to the proposal, the tunnel will contain a single track, and its cost has been estimated at about C1b.000,000. The scheme is of. considerable importance to Great Britain, since it would only he a matter of time l )C fore all-rail communication was established between Europe and the Union of South Africa, ns well as our African Dependencies.”