Page:Popular Science Monthly Volume 83.djvu/345

Rh. Railway traffic in Ireland would be further increased if a similar line crossed the channel from England to France, making through rail connection from Great Britain to the Continent. Under present conditions, ocean traffic from America to Ireland frequently goes first to Liverpool and thence back to Dublin or Belfast, with a corresponding delay. For local commerce between Ireland and the east, the time of transportation would be shortened by only two or three hours, and yet, for improving railway facilities from England to the north, the great Forth Bridge was built at a cost of $13,000,000.

One of the difficulties in connecting the railway systems of the Islands is the difference in their gauge, which is 4 feet 8½ inches, or standard width in England, and 5 feet 3 inches in Ireland. This difficulty could be overcome in some one of several ways, such as (1) transferring cargoes at the border, (2) changing all tracks to standard gauge, or (3) laying a third rail on both systems. Any of these methods would be costly, but a change would necessarily follow the construction of a channel road.

In selecting a location for the channel road, it will be found that the shortest distance across is from Tor Point in Antrim to the Mull of Cantyre, the length of which is fourteen miles, but this course would involve other difficult water crossings in Scotland, and the line would lead far to the northwest, making the course impracticable. A better location further south is that from Whitehead on the Irish coast, northeast of Belfast, to Port Patrick, the distance being twenty-three miles. An unfortunate feature of the latter course is the presence of a central valley or depression known as Beaufort's Dyke, the bottom of which is two or three hundred feet lower than other parts of the sea, which has a normal depth of 400 to 500 feet, making a total depth of 600 to 800 feet in this depression. Geologists declare that at one time there was no dividing sea, but only a central valley now known as Beaufort's Dyke, and during the Pleistocene period the land was submerged, forming the present Irish Sea and Channel.

There are at least four possible methods of establishing a railway across the channel: (1) a continuous embankment or causeway, (2) a submarine tunnel, (3) a submerged floating tube or viaduct and (4) a bridge.

A continuous embankment across the channel would cost at least $100,000,000, and possibly more, and it would interfere with shipping. It could be used for a double-track line of railway and for developing electric power from the strong northern current, which would be fifty times more productive of power than the whole Falls of Niagara. Such obstruction of the natural currents would, however, lower the water in the harbors of Glasgow, Liverpool, Belfast and Dublin, an objection of rather serious moment. Since the proposed causeway