The chief inspectors of districts are responsible for the general condition of the main lines, and it is their special duty to see that a uniform standard of maintenance is kept up by each of their sub-inspectors, and that orders given by the engineer are duly observed and consistently followed out. They arrange the running of trains of materials, and provide for ballasting operations, and are in constant communication with the divisional engineers, to whom they report upon every matter affecting the permanent way.
A similar chain of supervision exists in the workshops in each district.
Periodical meetings of the divisional engineers are held, at which the various points which arise from time to time in connection with the maintenance and repair of the permanent way are discussed, and the engineers are thus enabled to compare notes and give each other the benefit of their respective experience.
The stability of the permanent way and works of a great railway is frequently threatened, and ceaseless vigilance has to be exercised to avert the dangers arising from circumstances which no human foresight can anticipate. Embankments and sea-walls are sometimes demolished by storms; landslips and the fall of rock from overhanging cliffs may cover the rails; sudden subsidences of the surface, due to mining operations, may take place; bridges and viaducts may be set on fire, or washed away by floods; dangerous compounds explode in transit, rails be torn up by collisions, or portions of tunnels may collapse. Instances of mishaps from all these causes have occurred in actual experience, and to repair the damage and restore the communication in the shortest possible time is the task which frequently
