Shannon on Derailments.

Shannon Carefully examines the various causes of derailments, and classifies them thus:—

(a) Incorrect gauge.

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(b) Defects of surface, slacks and humps. (Slacks as a cause of derailments are regarded by Shannon as of such significance that he devotes, in the chapter thereon, 945 words to the subject.)

(c) Track out of alignment—“kick outs.”

(d) Unsuitable cant on curves.

(e) Curve worn rails.

(f) Broken rails.

(g) Points which may be open, or have a tendency to open.

(h) Defects in vehicles—defective springs, broken axles, worn or loose tyres.

(i) Difference in heights of coupled vehicles.

(j) Defects which may cause the frame of bogies to bind or catch on the main truck frame.

(k) Speed too high. (The only limitation of speed is due to sharp curvature, rough and weak track and unsuitable vehicles. (See previous reference to speed and “Beaton on Speed.”)

(l) Sudden application of brakes. (See previous reference to this under “Theory of Bunching”)

(m) Unequal distribution of the moveable load on the various wheels.

(n) Coupling of vehicles having different amount of overhang (shorts between bogies).

(o) Moving points when the train is passing over them.

(p) Propulsion of a heavy train round sharp curves.