1 MARCH 2000
20. MISCELLANEOUS TRACK APPLIANCES.
(1) Application and Type. Derails are commonly used on spur tracks or sidings to prevent runaway
cars or unauthorized entry onto the main track. Derails are also used to protect standing equipment
stored on a track. Three different types are the switch point derail, permanent hinged or sliding derail,
and portable derail.
(2) Location. Derails should be located so that after running over the derail, a car would stop before
reaching the point requiring protection. This distance depends mainly on track length and gradient.
Figure 6-32 illustrates derail placement.
Figure 6-32. Location of Derails