Many a time only the keen watchfulness of an engine-driver, or his assistant, the fireman, saved a train from dashing into some gravel heap, beneath which the rails were buried, or from plunging into some yawning opening from which a culvert or small bridge had been washed out. Nor with all this watchfulness did the trains always get through in safety. Sometimes a bit of track, that looked all right, would suddenly sink beneath the weight of a passing train into a quagmire that had been formed beneath it, and then would follow the pitiful scenes of a railroad wreck.