CEMP-E
TI 850-02
AFMAN 32-1125(I)
1 MARCH 2000
Key to Table 7-1:
Traffic Category
Description (See Note Below)
I
Up to 1% traffic 2-axle trucks.
II
1-10% 2-axle trucks.
III
Up to 15% traffic 2-axle trucks, up to 1% trucks with 3 or more axles.
IV
Up to 25% traffic 2-axle trucks, up to 10% trucks with 3 or more axles.
IV-A
More than 25% truck traffic, all types.
V
Tracked vehicles up to 60,000 lb gross weight.
VI
Tracked vehicles up to 90,000 lb gross weight.
VII
Tracked vehicles up to 120,000 lb gross weight.
Crossing Type
Description
1
Gravel Crossing with Timber Flangeway Header.
2
Timber Crossing.
3A
Asphalt Crossing.
3B
Asphalt Crossing with Timber Flangeway Header.
3C
4-Rail Asphalt Crossing.
3D
6-Rail Asphalt Crossing.
4A
Cast-in-Place Concrete Crossing.
4B
Prefabricated Concrete Panel Crossing.
4C
Sectional Monolithic Concrete (No Ties).
5
Full Depth Rubber Crossing.
NOTE: More detailed description of Road/Street Classes and Traffic Categories can be found in TM 5-822-2/AFM
88-7, Chap. 5, including provision for forklifts.
(3) Constructed Surfaces. Crossing types 1, 3A through D, and 4A may be categorized as
constructed crossings. With this type, the road or street is basically extended across the track to form a
crossing. Separate flangeway headers may be used, but the crossing is generally made from available
road and track materials and fabricated on-site. This arrangement provides site-specific versatility to fit a
crossing in-place at the time of construction. These crossings are readily adaptable to any track
curvature, super-elevation, or gradient. Generally, these crossings cannot be readily removed and
replaced when track or road maintenance is required.
(4) Prefabricated Surfaces.
(a) Crossing Types 2, 4B, 4C, and 5 may be categorized as prefabricated. These crossings are
generally ordered from a manufacturer and are assembled at the site from surface panels using special
panel attachment or track fastening hardware. Prefabricated crossings often require longer ties than
standard and must be ordered specifically for the size of rail and tie plates, and anchors (if used) at the
crossing; this ensures panel height will match rail height and that sufficient clear space is available under
the panels for the tie plates and rail fastenings. Prefabricated crossings must also be ordered to match
any track curvature and for crossing angles that vary significantly from 90 degrees. It is suggested that
prefabricated crossings be ordered to extend at least 2 ft on each side beyond the widest part of the road
through the crossing, allowing for crossing angle as needed.
7-3
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