How does coal dust damage track?
The coal dust in the Joint Line roadbed prevented the proper drainage function of the ballast when coupled with higher than normal rainfall and snow. The impaired drainage caused the rail level to become uneven and the surface of the ballast to degrade. When the roadbed does not properly support the track, the passage of coal trains breaks concrete ties and that in turn causes the rail to spread apart. Switches and bridges also sustain more damage. Such damage caused the derailments on May 14 and May 15 and the issuance of slow orders. These photographs illustrate the nature and extent of the damage.
