Figure 4.2. Guard Rails on Single-Track Bridge.
The guard rails should extend some distance beyond each end of the bridge and converge toward the track
center. The distance which they should extend varies. One rule of thumb says it should be as much as a rail
length; another rule sets it at 50 feet or about a car length. However, the important dimension is the 10 inches
given a few sentences back. It must be established before the guard rail reaches the bridge itself and remain
constant throughout its length.
SIZES AND SOURCES
Reconditioned running rails are often used as guard rails, but only if they are no larger in section than
their adjacent traffic rails; it is generally desirable that they be smaller. The following are good combinations: