Bypass Difficult (Figure 1-12). This bypass has the same conditions as bypass
easy, except that it will require some work to prepare the bypass. Preparation work will
usually take less than 3 hours.
Figure 1-12. Bypass-Difficult Symbol
Bypass Impossible (Figure 1-13). This symbol shows that the obstacle can
only be crossed by one of the following methods:
Repair of the item (for example, bridge). The repairs usually will
exceed 3 hours.
Detour using an alternate route that is some distance away.
Figure 1-13. Bypass-Impossible Symbol
1-13. Level-Grade Railroad-Crossing Symbol. This symbol (Figure 1-14) shows where
train tracks cross the route. Passing trains will interrupt traffic flow, so this symbol must
be shown on an overlay. If there is an overhead obstruction, an X with a line pointing to the
location of the overhead obstruction is used. Beside the X is the distance for minimum
overhead clearance. Anytime the overhead clearance is less than 4.3 meters, the given
distance for overhead clearance must be underlined. If an overhead obstruction exists
without a railroad crossing, an X is used alone.
Figure 1-14. Level-Grade Railroad-Crossing Symbol