has to be undertaken by the railway engineer, occurrences of the nature referred to frequently happening without the least previous warning. In such cases, the first difficulty the engineer experiences is very often in ascertaining, with any degree of accuracy, what has actually taken place, and the precise extent of the damage which has resulted, and he has next to determine what, with the time and means at his disposal, he is justified in attempting. It is often found that men, plant, and material can be more expeditiously obtained from some central depôt than from local resources, although the depôt may be a hundred miles or more from the scene of operations.
A notable illustration of what can be done in this way in an emergency by a company like the London and North-Western, possessing great resources, occurred when, in the great storm of Sunday, the 17th August, 1879, the Llandulas viaduct, on the main line of the Chester and Holyhead Railway, was undermined By flood, and washed completely away, interrupting, for the time being, the traffic between England and Ireland. For two days, until the flood subsided, nothing could be done, but within the space of five days afterwards the railway was deviated for about half-a-mile so as to strike the river at the narrowest point, and a temporary trestle bridge was erected, over which the first train passed at 2 p.m. on the 24th August, exactly seven days after the mishap occurred. The line was cut in the slope of the embankment leading to the old viaduct, and was everywhere placed upon solid ground, or upon stacks of old sleepers, so that there might be no settlement, and the line might be fit for the heaviest traffic immediately it was completed. The
