Section 2: Railroad Crossing SurfacesAnchor: #i1000582
Crossing Surface Details
Railroad crossing surfaces typically include the following characteristics:
- Surface is made of precast concrete panels 8 feet in length along the length of the track.
- Composite material may be used in lieu of concrete in areas of significant truck traffic where material will not degrade in climate conditions.
- Asphalt may be used in lieu of concrete, particularly for temporary crossings during construction.
- Timber crossings are rarely used anymore.
- Panels are bolted directly into railroad ties beneath.
- Panels installed between the rails are referred to as gauge panels while panels between the rails and the roadway surface are referred to as field panels.
- Rubber flangeways are installed between rails and concrete panels to prevent electrical shorting of the rails.
- A drainage pipe may be installed parallel to the rail on either or both sides of the rail.
- When replacing panels, the railroad company typically replaces the subballast, ballast, ties, and rail at the crossing and beyond roadway edges.
- Track panels are typically assembled in 80 foot preassembled sections, which include rail and ties bolted together (without crossing surface panels).
- Existing track is cut and removed and new track panel is jointed (bolted) to existing rail.
- New track panel is welded to existing track after crossing surface panels are installed.
- The railroad company uses a tamping machine to install and adjust ballast.
- Surfaces may take a few days or weeks to settle after train and truck traffic use the crossing.
- Adjustment of roadway elevation may be needed after crossing surface settles; this is typically done by adding asphalt level-up near the crossing surface.
Inspecting Crossing Surface Panels
Crossing surface panels wear over time due to:
- truck traffic
- train traffic
- presence of a humped or dipped crossing
- soil conditions
- lack of base material
- drainage problems.
Typical crossing surface panels may last from seven to 15 years depending on various conditions, but can last for shorter periods of time in particularly harsh environments. Before deciding to replace a crossing surface panel, consider the following:
- Does the entire surface need to be replaced or only portions with obvious wear?
- Are panels rocking? If so, are trucks snagging the edges of the field panels due to a humped crossing condition?
- Is the crossing draining properly so existing soil is not settling under the crossing?
- Would changes to the material or thickness of material under the subballast improve the crossing?
- Would a different crossing material work better than what is existing based on the truck traffic and climate?
- What can be done on the crossing approaches to smooth the crossing?
These factors should be considered in whether or not the Replanking Program should be used or supplemented as a means to improve the crossing surface. The railroad company has final authority in determining if a crossing can be repaired or a full replacement is needed.