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Rail Systems

The first consideration in selecting a rail system must be safety. Safety requirements are primarily determined by the needs of the expected trail users. Fitting rail types into appropriate Recreation Opportunity Spectrum classifications is done through material selection and/or coatings. Construction specifications also influence which rail system is suitable for a specific location and use. The basic rail systems include:

  1. Urban and High-Risk Areas (IBC-based)
    The 2006 International Building Code (IBC) refers to the rail systems that are attached to buildings, such as visitor centers, as guards. These rail systems are recommended on trail bridges in urban settings and high-use areas as well, for the protection of children. This code (IBC 1013, Guards and IBC 1607, Live Loads) requires a guard (rail system) at least 42 inches high. A 4-inch sphere must not pass through the lower 34 inches of the rail system and an 8-inch sphere must not pass through the upper part of the rail system, from 34 to 42 inches.

  2. Rural and Moderate-Risk Areas (AASHTO-based)
    Rail systems on trail bridges frequently used by children must meet the American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Highway Bridges. This code (LRFD section 13, Railings) requires a railing (rail system) at least 42 inches high for pedestrian traffic and at least 54 inches high for bicycle or equestrian traffic. A 6-inch sphere must not pass through the lower 27 inches of the rail system and an 8-inch sphere must not pass through the upper part of the rail system, higher than 27 inches.

  3. Remote and Low-Risk Areas (OSHA–based)
    The Occupational Safety and Health Administration (OSHA) refers to rail systems as standard railings. This code (OSHA 1910.23) provides safety without complication and is widely accepted for protecting industrial workers. Rail systems on remote trail bridges must be at least 42 inches high for pedestrian traffic and at least 54 inches high for bicycle or equestrian traffic. These rail systems must also have one or more intermediate rails so that the vertical distance does not exceed 15 inches between 2 x 4 wood rails and does not exceed 19 inches between steel rails.

Not all trail bridges require rail systems. An analysis should be completed to identify and evaluate the bridge's potential users and the hazards of not having a rail system. The analysis should also include the possibility of using a railing on only one side of the bridge. If the trail on which the bridge is located has more hazardous drops than the trail bridge, then a rail system is probably not required. Other considerations, such as convenience, may justify a rail system. As a general rule, any trail that is not in a remote areas with a drop of 4 feet or more, or a remote trail with a drop of 8 feet or more, should have a rail system. All trail bridges that do not have a rail system must have a curb.