Chapter 7: Exhibit A and PS&E Design

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Section 1: Common Rail-Highway Design Issues

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New At-Grade Crossings

Most railroad companies strongly oppose public projects that introduce new at-grade crossings. New at-grade crossings add maintenance and liability costs to a railroad company. However, in some cases, new at-grade crossings are unavoidable and railroad companies are willing to allow them if two to three other existing public at-grade crossings are closed and anticipated traffic counts at the new crossing do not exceed the combined traffic counts of the closed crossings. The TxDOT RRD Rail Letting Section serves as the office of primary negotiation with the railroad companies in these scenarios.

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Frontage Roads

It is recommended that new frontage roads are designed as either:

Frontage roads crossing a rail line at grade are not desirable.

A U-turn before a rail line should consider a barrier to ensure errant vehicles do not drive onto the railroad tracks.

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Grade Separations

Overpasses are the preferred option versus underpasses for grade separations. Overpasses are preferred due to:

When designing overpasses, access to adjacent properties should be considered early during project development.

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Accessing Railroad Right of Way

The project designer should become familiar with the project site and determine how project work within railroad right of way will be constructed. Temporary at-grade crossings are discouraged and may add both project cost and risk. Whenever possible, designers should aim to design any temporary pavement, ramps or detours that assist a contractor in construction of the project to eliminate the need for a temporary at-grade crossing.

If a temporary at-grade crossing is needed, it should be included in the Exhibit A for the railroad company to review up front and will be included in the C&M Agreement.

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Oversize Vehicles

Whenever railroad protective devices are proposed, the crossing should be evaluated for any oversize vehicles that could damage railroad signal equipment. Possible solutions include:

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Advanced Flashers

At locations where the approach view of an at-grade crossing may be obstructed, the use of ground-mounted or overhead amber flashing beacons with the Grade Crossing Advanced Warning Sign (W10-1) may be considered. When used, the flashers should operate without any actuation, i.e., always flashing. Train activated beacons are no longer recommended. As an alternative, railroad provided cantilevered flashing lights may be used in lieu of amber flashing lights.

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Temporary Special Shoring

There may be cases with shoofly track alignments where temporary special shoring is needed to shore a track section adjacent to an open cut for:

Traditionally, temporary special shoring on transportation projects is designed by the contractor. The railroad company requires TxDOT obtain a fully designed temporary special shoring system included in Exhibit A and approved by the railroad company prior to letting.

The shoring must be designed in accordance with AREMA and any guidelines provided by the railroad company.

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Design Guidelines

For development of Exhibit A plans, project managers and designers are encouraged to familiarize themselves with the railroad company’s design standards, as well as TxDOT annotated exceptions, prior to design. While the railroad company does not formally accept these annotated exceptions, they are published to give TxDOT’s recommended practices to designers where a difference of opinion on certain guidelines exists. Many shortline railroad companies do not have established design guidelines. Designers are recommended to follow the BNSF/UPRR joint guidelines.

See the RRD website for railroad company design standards and guidelines. Additional design references are found in Chapter 14.

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Standard Sheets A

Traffic Safety Division (TRF) standard sheets which apply to rail-highway projects include:

These sheets should supplement other design materials used for at-grade crossing design and are inserted as part of the PS&E on construction projects. Refer to TRF website for more information.

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Railroad or Highway Relocation

Relocating a rail line or highway may be considered as a design option to:

Railroad relocation generally involves the complete rebuilding of railroad facilities, including the acquisition of new right of way. Designers should strive to avoid at-grade crossings on relocated rail lines. Zoning the property adjacent to the railroad as light and heavy industrial further isolates the railroad corridor from residential and commercial activity. Businesses and industries desiring rail service can relocate in this area.

Planning for highway relocations should consider routes that would eliminate rail-highway intersections by avoiding the need for access over railroad tracks or by providing grade separations.

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Humped Crossings

Vertical curves should be evaluated on all approaches over an at-grade crossing. Significant grades can cause the following problems:

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  • Low-clearance and long wheelbase vehicles can get stuck on the track at the crossing.
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  • Crossing surface or field panels can become loose or dislodged if a vehicle catches on the approach edge of the panel.
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  • 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:

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  • 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.
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  • For new at-grade crossings, follow the above guidance.
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  • 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:

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  • Installation of Low Ground Clearance Grade Crossing warning signs (W10-5 and W10-5P).
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  • Restricting use of crossing for low clearance and long wheelbase vehicles.
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  • 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.

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Passive Crossings

All passive public crossings must have a stop or yield sign installed with the crossbuck sign. Passive crossings must have:

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  • Sufficient approach sight distance down the tracks to allow a driver to stop before the crossing when an approaching train is seen.
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  • Sufficient sight distance down the tracks to allow a tractor-trailer to clear the tracks from a stop at the crossing before a train arrives.

All new public crossings are recommended to include active warning devices. Refer to Part 8 of the TMUTCD for more information.

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