Humped Crossings

Vertical curves should be evaluated on all approaches over an at-grade crossing. Significant grades can cause the following problems:
  • Low-clearance and long wheelbase vehicles can get stuck on the
    track at the
     crossing.
  • Crossing surface or
     field panels can become loose or dislodged if a vehicle catches on the approach edge of the panel.
  • Inadequate turning radius from the adjacent road, causing vehicles to leave the paved roadway, which could lead to the vehicle stalling on the crossing.
Adjusting the roadway profile to eliminate problems with humped crossings can add significant cost to the project. The following guidelines are
recommended
:
  • At an existing at-grade crossing, inspect the crossing for damaged,
    missing or
     dislodged field panels
    as well as any other damage
     on the approach pavement adjacent to the panels to determine if vertical clearance is an issue. The maximum approach grade should not exceed 3 inches of the rail elevation at a point 30 feet away from the center of the nearest rail on both sides of the crossing.
  • For new at-grade crossings, follow the above guidance.
  • The crossing may be widened and/or additional pavement installed to keep the design vehicle on asphalt when turning onto the crossing.
As railroad companies replace ballast over time during routine maintenance, the elevation of the rail will increase, adding to the problem.
Solutions for humped crossings include:
  • Installation of Low Ground Clearance Grade Crossing warning signs (W10-5 and W10-5P).
  • Restricting use of crossing for low clearance and long wheelbase vehicles.
  • Improving approach grades to the crossing,
    including any turning radii from an adjacent roadway
    .
Any changes to the crossing should be reported by the district railroad coordinator to
RRD, including installation of W10-5 signs so the TRIMS and Federal Railroad Administration crossing databases may be updated
.