The point at which trails cross active tracks is the area of greatest concern to railroads, trail planners, and trail users. Railroad owners, the FRA, and State DOTs have spent years working to reduce the number of at-grade crossings in order to improve public safety and increase the efficiency of service. RWT design should minimize new at-grade crossings wherever possible. Modifying an existing highway-rail crossing may be an option. Alternative options are below-grade (underpass), or above-grade (overpass) crossings, which are expensive and typically have been installed in limited circumstances, such as:
Some government agencies and railroad owners have adopted policies of no new at-grade crossings. In these cases, using existing crossings or building grade-separated crossings may be the only alternatives. Also, many railroads are actively working to close existing at-grade crossings to improve safety, reduce maintenance costs, improve operating efficiency, and reduce liability exposure. The RWT feasibility analysis should carefully evaluate all proposed crossings, with consideration given to:
The railroad company or agency, and State DOT or Public Utility Commission, will need to approve any new crossings, the design of which must be in compliance with the MUTCD.1"Relevant information also is contained in the Railroad-Highway Grade Crossing Handbook (FHWA, 1986) and U.S. DOT Highway-Rail Grade Crossings Technical Working Group (TWG) document, Guidance on Traffic Control Devices at Highway-Rail Grade Crossings (FHWA, 2002)
More than half the existing RWTs in the U.S. include some sort of track crossing, mostly at-grade (RTC, 2000). The Bugline Trail, Wisconsin, Southwest Corridor Park Trail, Massachusetts, Illinois Prairie Path, and Rock River Recreation Path, Illinois, have overpasses or bridges. The Tony Knowles Coastal Bicycle Trail, Alaska, has tunnels under the tracks, and the Springwater Corridor Extension, Oregon, will have two pedestrian underpasses.
Existing at-grade crossings typically have some sort of passive warning devices --railroad "crossbucks" or railroad crossing signs (see Figure 5.24 on page 75). Examples are on the Burlington Waterfront Bikeway, Vermont, and Lehigh River Gorge Trail, Pennsylvania. Several have active warning devices such as gates or alarms. Planned trails such as the Blackstone River Bikeway, Rhode Island, and Springwater Corridor Extension, Oregon, will have higher quality at-grade crossings, with a full complement of automatic gates, warning alarms, and signage.
Location of the Crossing
Trail-rail grade crossings should reduce illegal track crossings by channelizing users to safer crossing areas. Crossings must not be located where trains may be regularly stopped, since this would encourage trail users to cross between or under railroad cars -- an extremely dangerous and unacceptable movement. Crossings should not be located on railroad curves where sight lines are poor. When new at-grade crossings are not permitted, the RWT design will need to channelize users to cross the tracks at roadway locations (see p. 81) or develop a grade-separated crossing (p. 79).
Adequate sight distance is particularly important at trail-rail intersections that do not have active warning devices such as flashing lights or automatic gates. Bicyclists, pedestrians, and other trail users should be given sufficient time to detect the presence of an approaching train and either stop or clear the intersection before the train arrives.
Three elements required for safe movement of trail users across the railroad tracks are as follows:
Advance notice of the crossing
The first element concerns stopping sight distance, a common consideration in highway intersection design. The stopping sight distance is that distance required for a trail user to see an approaching train and/or the grade crossing warning devices at the crossing, recognize them, determine what needs to be done, and then come to a safe stop at a point 4.5 m (15 ft) clear of the nearest rail, if necessary. This point usually will be marked by a pavement marking in advance of the crossing. This sight distance is measured along the trail, and is based on a trail user traveling at a given speed, and coming to a safe stop as discussed above.
Traffic control device comprehension
The second element involves the recognition of the grade crossing warning devices by the approaching user. Trail users should be reminded of the meaning of all traffic control devices in use at grade crossings, such as the fact that the familiar crossbuck sign should be treated as a YIELD sign at any crossing, or that flashing lights without gates, when flashing, are to be treated the same as a STOP sign.
Ability to see an approaching train
The third element concerns the trail user's ability to see an approaching train in order to decide whether it is safe to cross. Two different kinds of sight distance considerations are involved for safe movement across the crossing. This third element involves the sight distance available in advance of the crossing, as well as the sight distance present at the crossing itself.
Approach sight distance (also known as corner sight distance) involves the clear sight line, in both directions up and down the tracks, that allows a trail user to determine in advance of the crossing that there is no train approaching and it is safe to proceed across the tracks without having to come to a stop. These sight triangles, dependent upon both train speed and trail user speed, are determined as shown in the Railroad-Highway Grade Crossing Handbook (FHWA, 1986).
Often these sight triangles are obstructed by vegetation, topography, or structures. If the clear sight triangles for a given trail user speed (bicyclists and skaters will probably be the fastest trail users) cannot be obtained, then the trail should have additional warning signs or a reduced speed limit posted in advance of the crossing. As another treatment, based upon local conditions and engineering judgment, STOP or YIELD signs may be placed on the trail at the crossing.
Clearing sight distance, which applies to all crossings without automatic gates, involves the clear sight line, in both directions up and down the tracks, present at the crossing itself. A trail user stopped 4.6 m (15 ft) short of the nearest rail must be able to see far enough down the track in both directions to determine if the user can move across the tracks, to a point 4.6 m (15 ft) past the far rail, before the arrival of a train. At crossings without gates that have multiple tracks, the presence of a train on one track can restrict a trail users' view of a second train approaching on an adjacent track.
A more detailed treatment of the sight distance problem at grade crossings may be found in the document titled, Guidance on Traffic Control Devices at Highway-Rail Grade Crossings (FHWA, 2002).
In addition, most railroad safety books and FRA Roadway Worker Safety rules (49 CFR 214), specify that upon the approach of a train, enough warning must be given to allow someone on the track to have at least 15 seconds between the time they are clear of the track and the time the train gets to their location. This criterion applies only to railroad personnel who are working within their established limits and are prepared to vacate the track structure with proper warning. Because the average trail user most likely is not familiar with the hazards of rail operations, they would need additional warning time.
Approach Grades and Angle
The AASHTO Bike Guide and ADA specify grade requirements for shared use paths. Trail grades over 5 percent are allowed for short distances in specific circumstances. Grades over five percent are not recommended for crossing approaches. In general, the trail approach should be at the same elevation as the track (see Figure 5.19). Steep grades on either side of the track can cause bicyclists to lose control, may distract trail users from the conditions at the crossing, and may block sight lines.
Another critical issue, particularly for bicyclists and people with disabilities, is the angle of crossing. The AASHTO Bike Guide makes the following statement with respect to the crossing angle of a bikeway at a railroad track:
"Railroad-highway grade crossings should ideally be at a right angle to the rails... The greater the crossing deviates from this ideal crossing angle, the greater is the potential for a bicyclist's front wheel to be trapped in the flangeway, causing loss of steering control. If the crossing angle is less than approximately 45 degrees, an additional paved shoulder of sufficient width should be provided to permit the bicyclist to cross the track at a safer angle, preferably perpendicularly."
Flangeway is the term used for the space between the rail and the pavement edge. The standard flangeway width for commuter and transit railroad crossings is 63.5 mm (2.5 in),76.2 mm (3 in) for freight railroads. These widths are greater than many bicycle tires and wheelchair casters. For this reason, acute angle crossings are not recommended. Also, according to the AASHTO Bike Guide, where active warning devices are not used to indicate an approaching train, the trail should cross the railroad at or nearly at right angles and where the track is straight (see Figures 5.20 and 5.21). Where the track is not straight (e.g., on a curve), complications exist: sight distance is restricted and the rails may be at different levels.