The Gaithersburg List


FEDERAL-AID POLICY GUIDE
December 9, 1991, Transmittal 1

23 CFR 646B

OPI: HNG-12

SUBCHAPTER G - ENGINEERING AND TRAFFIC OPERATIONS

PART 646 - RAILROADS

Subpart B - Railroad-Highway Projects

Sec.

Appendix - Horizontal and Vertical Clearance Provisions for Overpass and Underpass Structures

Authority: 23 U.S.C. 109(e), 120(d), 130, and 315; 49 CFR 1.48(b).

Source: 40 FR 16059, Apr. 9, 1975, unless otherwise noted.

Sec. 646.200 Purpose and applicability.

[40 FR 16059, Apr. 9, 1975, as amended at 45 FR 20795, Mar. 31, 1980]

Sec. 646.202 Authority.

This subpart is issued under authority of 23 U.S.C. 109(e), 120(d), 130, 315 and 405, Section 203 of the Highway Safety Act of 1973, 49 CFR 1.48.

Sec. 646.204 Definitions.

For the purposes of this subpart, the following definitions apply:

Sec. 646.206 Types of Projects.

Sec. 646.208 Funding.

Sec. 646.210 Classification of projects and railroad share of the cost.

Sec. 646.212 Federal share.

[40 FR 16059, Apr. 9, 1975, as amended at 47 FR 33955, Aug. 5, 1982]

Sec. 646.214 Design.

[40 FR 16059, Apr. 9, 1975, as amended at 47 FR 33955, Aug. 5, 1982]

Sec. 646.216 General procedures.

Sec. 646.218 implified procedure for accelerating grade crossing improvements.

Sec. 646.220 Alternate Federal-State procedure.

[40 FR 16059, Apr. 9, 1975; 40 FR 29712, July 15, 1975; 40 FR 31211, July 25, 1975; 42 FR 30835, June 17, 1977, as amended at 45 FR 20795, Mar. 31, 1980]

Appendix to Subpart B - Horizontal and Vertical Clearance Provisions for Overpass and Underpass Structures

The following implements provisions of 23 CFR 646.212(a)(3).

  1. Lateral Geometrics. A cross section with a horizontal distance of 20 feet, measured at right angles from the centerline of track at the top of rails, to the face of the embankment slope, may be approved. The 20-foot distance may be increased at individual structure locations as appropriate to provide for drainage if justified by a hydraulic analysis or to allow adequate room to accommodate special conditions, such as where heavy and drifting snow is a problem. The railroad must demonstrate that this is its normal practice to address these special conditions in the manner proposed.

    Additionally, this distance may also be increased up to 8 feet as may be necessary for off-track maintenance equipment, provided adequate horizontal clearance is not available in adjacent spans and where justified by the presence of an existing maintenance road or by evidence of future need for such equipment. All piers should be placed at least 9 feet horizontally from the centerline of the track and preferably beyond the drainage ditch. For multiple track facilities, all dimensions apply to the centerline of the outside track.

    Any increase above the 20-foot horizontal clearance distance must be required by specific site conditions the State highway agency (SHA) and the FHWA.

  2. Vertical Clearance. A vertical clearance of 23 feet bove the top of rails, which includes an allowance for future ballasting of the railroad tracks, may be approved. Vertical clearance greater than 23 feet may be approved when the State regulatory agency having urisdiction over such matters requires a vertical learance in excess of 23 feet or on a site by site is where justified by the railroad to the satisfaction of the SHA and the FHWA. A railroad's justification for increased vertical clearance should based on an analysis of engineering, operational /or economic conditions at a specific structure location Federal-aid highway funds are also eligible to participate in the cost of providing vertical clearance greater than 23 feet where a railroad establishes to the satisfaction of a SHA and the e the proposed grade separation project is located. The lan must cover a logical independent segment of the rail system and be approved by the railroad's corporate headquarters. For 25 kv line, a vertical clearance of 24 feet 3 inches may be approved. For 50 kv line, a vertical clearance of 26 feet may be approved.

    A railroad's justification to support its plan for electrification shall include maps and plans or drawings showing those lines to be electrified; actions taken by its corporate headquarters committing it tons initiated or completed to dateimplementing its electrification plan such as a showing of the amounts of funds and identification of structures, if any, where the railroad has expended its own funds to electrification. If available, the railroad's justification should include information on its ontemplated treatment of existing grade separations along the section of its rail system proposed for electrification.

    The cost of reconstructing or modifying any existing railroad-highway grade separation structures solely to accommodate electrification will not be eligible for Federal-aid highway fund participation.

  3. Railroad Structure Width. Nine feet of structure width outside of the centerline of the outside tracks may be approved for a structure carrying railroad tracks. Greater structure width may be approved when in accordance with standards established and used by the affected railroad in its normal practice.

    In order to maintain continuity of off-track equipment roadways at structures carrying tracks over limited access highways, consideration should be given at the preliminary design stage to the feasibility of using ublic road crossings for this purpose. Where not feasible, an additional structure width of 8 feet may be approved if designed for off-track equipment only.

[53 FR 32218, Aug. 24, 1988]


United States Department of Transportation - Federal Highway Administration

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