Table 7-1. Recommended Crossing Surfaces

CEMP-E

TI 850-02

AFMAN 32-1125(I)

1 MARCH 2000

c. Geometric Layout.

(1) The ideal crossing geometry is a 90-degree intersection of the track and road (for best sight

angles) with slight ascending grades on the road approaches. Drainage should be away from the track to

reduce the flow of surface water toward the crossing.

(2) Avoid locating crossings near road intersections.

(3) Avoid locating crossings within either a road or railroad curve. These sites typically result in poor

sight warning distances and in conflicting super-elevations that often lead to long-term maintenance

problems and poor performance of the crossing.

(4) Where the road and railroad cannot cross at right angles, the angle should be kept to 60 degrees

or greater whenever practical. For angles less than 60 degrees additional warning or crossing protection

should be considered.

d. Crossing Surfaces and Flangeways.

(1) Table 7-1 lists 10 standard crossing types. Figures 7-1 through 7-10 show cross sections and

design details, These designs are described below along with some recommendations for their

application and their limitations. It should be noted that, even for the most expensive crossing surfaces,

the cost of rebuilding the track (especially when new rail is installed) and the road approaches is usually

more than the purchase and installation cost of the crossing surface itself. Thus, especially where road

traffic volume is significant, where significant numbers of heavy trucks pass over the crossing, or where

vehicle speeds exceed 25 mph, the main cost variable will probably be the expected durability of the

crossing.

(2) Table 7-1. This table is a starting point for matching a crossing surface with traffic requirements.

The descriptions of the crossing surfaces below will help focus on the most appropriate choices. The

Road/Street classes (A through F) and Traffic Categories (I through VII) in table 7-1 are those from TM 5-

822-2/AFM 88-7, chapter 5. The entries in the table are the codes for the suggested crossing surfaces.

Table 7-1. Recommended Crossing Surfaces

Road/Street Class

Traffic

A

B

C

D

E

F