Chapter 5--Designing Trail Crossings and Structures--Continued
Routing horse trails along active railroad corridors generally is ill-advised. Most riders don't want to ride on a trail adjacent to active rail tracks. Train speeds, sounds, vibrations, and size are threatening to stock that are not familiar with them. Controlled crossings with crossing bells, sirens, horns, lights, or traffic gates can frighten stock and cause them to become uncontrollable. However, in limited circumstances horse trails or crossings in railroad corridors may be unavoidable (figure 5-6).
For safety reasons, most railroad companies are reluctant to allow other uses within their rights-of-way. Railroad rights-of-way are private property--walking or riding there without explicit authorization from the railroad company is trespassing.
Arrangements to use railroad corridors or crossings require extensive negotiation between trail developers, governing jurisdictions, and property owners. Safety arrangements have to be negotiated in areas where proposed equestrian trails will be close to railroads.
Locating horse trails or crossings in active railroad corridors is a lengthy and costly process. Permits, easements, or rights-of-way are an absolute necessity. In addition, stringent safety and liability issues must be addressed. When at-grade railroad crossings intersect highways, they also are subject to the governing highway authority. Frequently, the highway authority pays to install crossing signs and signals on highways, and the railroad maintains them.
Trails parallel to active railroad tracks are called rails-with-trails (RWTs). Don't mistake RWTs for rails-to-trails, which follow former--or inactive-- rail lines. Safety is the most important factor when designing RWTs that include riders. According to Rails-with-Trails: Lessons Learned (Alta Planning and Design 2002): "Trail width is an overriding design issue when considering equestrian use on RWTs. RWTs designed to accommodate equestrian use should provide separate treads for multiple users. Narrow rights-of-way that afford width for only a single paved trail, or that provide inadequate shy distance for a horse frightened by near or oncoming trains are not appropriate candidates for accommodation of equestrian use. Trestles and bridges require additional considerations. Many horses are frightened by bridges and other elevated environments, particularly lattice or perforated bridges and trestles that allow the animal a view of the ground substantially below the bridge deck. Most horses are not accustomed to this environment and will respond unpredictably with potentially negative consequences."
Because there are no national planning standards or guidelines for trail setback distances parallel to active railroads, guidance must be pieced together from relevant standards for shared-use trails, pedestrian facilities, railroad facilities, and/or railroad crossings or railroad rights-of-way. Consider these factors (Alta Planning and Design 2002) during trail feasibility studies:
- Type, speed, and frequency of trains in the trail corridor
- Maintenance needs
- Applicable State standards
- Separation techniques
- Historical problems
- Track curvature
- Engineering judgment
Because every case is different, determine the setback distance and other considerations on a case-by-case basis after engineering analysis and consideration of liability concerns.
Generally, horses and mules can maneuver over railroad tracks that intersect trails when the crossing is wide enough and has solid, level footing--at the approach, between the rails, and on the opposite side of the railroad track. Trails, roads, or sidewalks should approach a railroad crossing perpendicular to the direction of train travel. Build the tread surface level with the top rail flange, filling in the gap (figure 5-7) as specified by railroad regulations. Materials commonly used to fill the gap include concrete, asphalt, hardened rubber, wood planks, gravel, or other durable materials. Rubber or concrete lasts longer than wood or asphalt and requires less maintenance. When trails cross abandoned tracks, consider removing the rails and ties.
Figure 5-7--Building a horse trail in an
active railroad corridor requires extensive
negotiation to address safety and liability
concerns for trail users and railroad personnel.
If trails must cross tracks, the tread should be
level and the gaps filled according to railroad
requirements. Trails also must approach
tracks at a 90- degree angle.
Railcars overhang the tracks by 3 feet (0.9 meter) on each side, and trains need a dynamic operating space for loose loads or straps and thrown debris. To reduce the hazards associated with stock waiting for a train to pass through a crossing, a waiting area may be appropriate. Locate waiting areas back and away from rails as required at each site to meet the needs of trail users and railroad personnel.
Recreation trails generally cross water at grade or above. Constructing a crossing over or through water generally requires authorization from the governing authority and may require special construction techniques or environmental considerations. Horse trails may incorporate bridges or culverts to maximize habitat protection and reduce trail maintenance. Sometimes fording a stream is the best option.
Locate fords in an area where the stream is straight and shallow, avoiding areas that are deeper than 2 feet (0.6 meter) during most of the use season. Avoid locations where the stream turns, because water undercuts the outside bank. Routing the trail to a good natural ford is better than building a new ford. When constructing a ford across a shallow stream, stabilize banks to prevent sedimentation, if necessary. Figure 5-8 shows a ford that crosses a fish ladder. Where suitable, angle trail approaches upstream to protect the bank from erosion caused by rising water. To block rising water from running down the main trail, construct approaches so they climb a short distance above the usual high water line (figure 5-9). Options for stabilizing banks include the use of geotextiles in combination with riprap. Figure 5-10 shows installation of soil-filled geocell layers to stabilize a bridge approach. Articulating and interlocking concrete pavers are other options for stabilizing streambeds. Pavers with voids for soil or plant material are less likely to be a slip hazard. Figure 5-11 shows interlocking hard pavers used to stabilize a bridge approach.
Figure 5-8--This fish ladder includes a ford
for trail users while still allowing trout
to move up the creek. The steps have
big landings--about 8 to 10 feet long--and
stock tolerate them. The rocks alongside
the ford keep stock on the desired path.
Figure 5-9--This ford has a rock step up
to a landing. The trail approach rises to
keep the stream from flowing down the
tread. Rocks on the side of the ford
guide stock to the step.
Caution: large, wet rocks can be hazardous for all trail users.
Figure 5-11--The approach to this trail bridge
is reinforced with interlocking pavers
to withstand wear from off-highway vehicle
use. The pavers may not offer enough traction for
horses and mules. A similar approach using
horse-friendly pavers could be
used on equestrian bridges.
Provide solid footing, such as medium-sized gravel or a stabilized surface. Place it at a consistent depth from one bank to the other (figure 5-12). Choose the surface materials carefully--hardened surfaces reduce sedimentation and stream erosion, but can be slippery when wet.
Curbs that run across treads and smooth, hardened tread edges at water crossings are trip hazards and are not appropriate for horse trails. Natural rocks and crushed gravel can help sustain the edges of stream crossings when stabilization is necessary (figure 5-13). Do not include fines that will wash away. To prevent steep dropoffs, gradually transition from the tread to stream bottom. The underwater portion of the tread may need to be wider than the rest of the trail to accommodate stock that step to the side. On Forest Service horse trails, fords have a trail base that is at least 3 feet (0.9 meter) wide. Consult an engineer or hydrologist for additional techniques to stabilize fords and areas nearby. Figure 5-14 shows a concept for an urban channel crossing at grade. Geosynthetics stabilize the banks.
Figure 5-13--Rocks and gravel can be used
to reduce erosion along waterways,
but medium and large rocks can be
slippery when wet. These riders chose the side
of the tread with the best horse
footing--small rocks and gravel.
Fords get the most use when flows are low to moderate and are not intended for use during high runoff. Where fords traverse water with a strong current, the downstream side should be free of dangerous objects. Place pedestrian bridges or stepping stones on the upstream side of the equestrian bridge to prevent fallen stock from being swept into other trail users or pinned against structures.
In areas where at-grade stream crossings are not suitable, consider elevating the tread. Causeways, turnpikes, boardwalks, and puncheon bridges are construction methods that minimize damage to wet areas. These techniques often are used in combination with rock, fill, and geosynthetics, where permitted. Determine the type of support and drainage systems that will safely withstand the weight of stock on elevated trail treads.
Turnpikes incorporate fill material taken from parallel side ditches and from offsite to build the trail base higher than the surrounding water table on wet or boggy ground (figure 5-15). Turnpikes are practical in areas with a trail grade up to 10 percent and in flat areas with 0- to 20-percent sideslopes. Use turnpike construction to provide a stable trail base in areas with a high water table and fair- to well-drained soils.
To build a turnpike, ditch both sides of the trail to lower the water table. Next, install geotextile, or other geosynthetic materials, and retainer logs or rocks. Place the geotextile under any retainers. Lay the geotextile over the ground with no excavation, and then add high-quality fill.
The two most important considerations when constructing a turnpike are lowering the water level below the trail base and carrying the water under and away from the trail at frequent intervals. Turnpikes require some degree of drainage. A turnpike is easier and cheaper to build than puncheon and may last longer. Use puncheon when the ground is so wet that drainage is impossible and grading is precluded.
A more environmentally friendly relative of the turnpike is one without side ditches. Sometimes turnpikes without ditches are called causeways. In the Sierra Nevada, causeways filled with crushed rock create elevated, hardened treads across seasonally wet alpine meadows. A single causeway often replaces multiple, unwanted parallel treads. These causeways create less environmental impact than turnpikes, because they lack ditches and don't lower the water table. The risk is that turnpikes without ditches could sink into highly saturated soils, a problem mitigated by geotextiles. The encapsulation technique sometimes works well on causeways.
Puncheon is a wood walkway used to cross bogs or deep muskeg, to bridge boulder fields, or to cross small streams (figure 5-16). Puncheon can be constructed where uneven terrain or inadequate tread material makes turnpike construction impractical. It is easier to support puncheon on muddy surfaces than to construct a turnpike.
Puncheon resembles a short log-stringer trail bridge that has a deck made of native logs or sawn, treated timber. The deck of surface puncheon is placed on stringers to elevate the trail across wet, difficult-to-drain areas. The Student Conservation Association (Birkby 2006) constructs puncheon for horse trails using log stringers that are at least 10 inches (254 millimeters) in diameter and decking that is at least 4 inches (102 millimeters) thick. The puncheon is 48 inches (1,219 millimeters) wide.
Subsurface puncheon is placed flush with the wetland surface. Creating subsurface puncheon involves constructing mudsills, stringers, and decking under the surface. This design depends on continual water saturation for preservation. To improve traction, cover the surface between the curb logs with a layer of gravel, wood chips, or soil.
In areas with deep mud, sometimes trail users find it difficult to see and follow the trail on subsurface puncheon. Once an animal steps off the tread, it can severely damage the area when attempting to regain solid footing. If the animal becomes trapped in muck, it may be very difficult or impossible to get it out alive.
Boardwalks have multiple pilings, and are essentially a series of connected bridges. Horse trails rarely have boardwalks.
Install longitudinal edging--retaining curbs--to delineate the edges on elevated treads or puncheon (see figures 5-15 and 5-16). Treat elevated treads, such as boardwalks, as if they were a bridge and use the guidelines for equestrian bridge designs.