Deb Mucci, Mechanical Engineering Technician;
Brian Vachowski, Project Leader
The Southwest Montana ATV (all-terrain vehicle) Trail Cattle Guard (MTDC-1049) has been developed to replace an earlier design, the Deerlodge Trail Cattle Guard (MTDC-951-2). The Deerlodge Trail Cattle Guard proved to be too short (only 34 inches on each side of a wire fence) to prevent livestock from trying to jump over it. Also, cattle got their legs caught in the 4-inch gap between the rails and could not free themselves. The Deerlodge Trail Cattle Guard was featured as one of four OHV (off-highway vehicle) trail cattle guard designs in MTDC's 1998 report, Cattle Guards for Off-Highway Vehicle Trail (9823-2826-MTDC), available at: www.fhwa.dot.gov/environment/fspubs/98232826/
Eric Tolf from the Beaverhead-Deerlodge National Forest and Tim Hippert from McGrew Machine and Fabricating, Inc., designed the Southwest Montana ATV Trail Cattle Guard, borrowing some ideas from other designs (figure 1). The deck is fabricated from 2- by 1-inch steel channel, with a 6-inch gap between the pieces of channel. The two halves of the deck join at the middle. The halves can be bolted to each other, or to wooden fenceposts. Attaching the halves directly to the posts will not reduce the effective width (54 inches) of the cattle guard.
The deck is about 22 inches above the ground and the top of the sides are about 51 inches above the ground. The sides flare out from the bottom to the top, providing a visual cue to keep cattle from trying to jump the cattle guard, and serving as a physical barrier to stop ATVs from sliding off the cattle guard. The cattle guard is painted with flat brown oil-based paint.
Figure 1--The Southwest Montana ATV Trail Cattle Guard
is being used on national forests and BLM public lands
in Montana. Object markers may be placed on the center posts
instead of on fiberglass stakes at the corners.
Usually, these cattle guards are installed along an existing fence. Choose crossing locations where cattle are not accustomed to bunching up, because cattle that are pushed or bunched up may be forced to step onto the cattle guard or may be tempted to jump it. Sites need to be fairly level. Preservative-treated timbers or thick planks usually are placed beneath the structure, with the soil excavated so that the buried timbers are nearly flush with the ground surface. Timbers support the cattle guard and help keep it in place. Lag screws fasten the cattle guard to the timbers.
Typically, treated wood fenceposts are part of a brace panel that supports the fence on both sides of the cattle guard. Although the two halves of the deck can be screwed directly to these posts, normally they are bolted to each other instead of to the posts.
Yellow retroreflective object markers are mounted on each side of the two posts to help ATV riders see the edges of the structure after dark. Instead, markers could be placed on flexible fiberglass stakes or posts at each of the four corners of the cattle guard. The markers (figure 2) may be type 2 or modified type 2 object markers. If a cattle guard constricts or narrows the trail, the larger type 3 object markers (figure 2) may be required. In the Forest Service, a recreation review serves to document the size and type of object markers that are needed.
Figure 2--The type 2 or modified type 2 object markers
meet Forest Service guidelines, except where the cattle
guard narrows or constricts a wide trail. In such cases, the
type 3 object marker may be needed as determined by
a recreation review.
The cattle guard can be fabricated from the drawing on the inside pages. McGrew Machine and Fabricating, Inc., Whitehall, MT, fabricates and sells these cattle guards. Please contact the MTDC for a copy of the drawing using the information below.
McGrew Machine and Fabricating, Inc.
5 South Division St.
Whitehall, MT 59759
Grant Godbolt, Beaverhead-Deerlodge National Forest
Tim Hippert, McGrew Machine and Fabricating, Inc.
Donna Sheehy, Northern Region, USDA Forest Service
Eric Tolf, Beaverhead-Deerlodge National Forest
Additional single copies of this document may be ordered from:
USDA Forest Service, Missoula Technology and Development Center
5785 Hwy. 10 West
Missoula, MT 59808-9361
For additional information about improved ATV trail cattle guards, contact Brian Vachowski at MTDC.