49 CFR Appendix A to Part 237, Supplemental Statement of Agency Policy on the Safety of Railroad Bridges
A Statement of Agency Policy on the Safety of Railroad Bridges was originally published by FRA in 2000 as Appendix C of the Federal Track Safety Standards, 49 CFR Part 213. With the promulgation of 49 CFR Part 237, Bridge Safety Standards, many of the non-regulatory provisions in that Policy Statement have been incorporated into the bridge safety standards in this part.
However, FRA has determined that other non-regulatory items are still useful as information and guidance for track owners. Those provisions of the Policy Statement are therefore retained and placed in this Appendix in lieu of their former location in the Track Safety Standards.
1. The structural integrity of bridges that carry railroad tracks is important to the safety of railroad employees and to the public. The responsibility for the safety of railroad bridges is specified in § 237.3, “Responsibility for compliance.”
2. The capacity of a bridge to safely support its traffic can be determined only by intelligent application of engineering principles and the law of physics. Track owners should use those principles to assess the integrity of railroad bridges.
3. The long term ability of a structure to perform its function is an economic issue beyond the intent of this policy. In assessing a bridge's structural condition, FRA focuses on the present safety of the structure, rather than its appearance or long term usefulness.
4. FRA inspectors conduct regular evaluations of railroad bridge inspection and management practices. The objective of these evaluations is to document the practices of the evaluated railroad, to disclose any program weaknesses that could affect the safety of the public or railroad employees, and to assure compliance with the terms of this regulation. If the evaluation discloses problems, FRA seeks a cooperative resolution. If safety is jeopardized by a track owner's failure to resolve a bridge problem, FRA will use appropriate measures, including assessing civil penalties and issuance of emergency orders, to protect the safety of railroad employees and the public.
5. This policy statement addresses the integrity of bridges that carry railroad tracks. It does not address the integrity of other types of structures on railroad property (i.e., tunnels, highway bridges over railroads, or other structures on or over the right-of-way).
6. The guidelines published in this statement are advisory. They do not have the force of regulations or orders, which FRA may enforce using civil penalties or other means. The guidelines supplement the requirements of part 237 and are retained for information and guidance.
1. Responsibility for safety of railroad bridges.
(a) The responsibility for the safety of railroad bridges is specified in § 237.3.
(b) The track owner should maintain current information regarding loads that may be operated over the bridge, either from its own engineering evaluations or as provided by a competent engineer representing the track owner. Information on permissible loads may be communicated by the track owner either in terms of specific car and locomotive configurations and weights, or as values representing a standard railroad bridge rating reference system. The most common standard bridge rating reference system incorporated in the Manual for Railway Engineering of the American Railway Engineering and Maintenance-of-Way Association is the dimensional and proportional load configuration devised by Theodore Cooper. Other reference systems may be used where convenient, provided their effects can be defined in terms of shear, bending and pier reactions as necessary for a comprehensive evaluation and statement of the capacity of a bridge.
(c) The owner of the track on a bridge should advise other railroads operating on that track of the maximum loads permitted on the bridge stated in terms of car and locomotive configurations and weights. No railroad should operate a load which exceeds those limits without specific authority from, and in accordance with restrictions placed by, the track owner.
2. Capacity of railroad bridges.
(a) The safe capacity of bridges should be determined pursuant to § 237.71.
(b) Proper analysis of a bridge requires knowledge of the actual dimensions, materials and properties of the structural members of the bridge, their condition, and the stresses imposed in those members by the service loads.
(c) The factors which were used for the design of a bridge can generally be used to determine and rate the load capacity of a bridge provided:
(i) The condition of the bridge has not changed significantly; and
(ii) The stresses resulting from the service loads can be correlated to the stresses for which the bridge was designed or rated.
3. Railroad bridge loads.
(a) Control of loads is governed by § 237.73.
(b) Authority for exceptions. Equipment exceeding the nominal weight restriction on a bridge should be operated only under conditions determined by a competent railroad bridge engineer who has properly analyzed the stresses resulting from the proposed loads and has determined that the proposed operation can be conducted safely without damaging the bridge.
(c) Operating conditions. Operating conditions for exceptional loads may include speed restrictions, restriction of traffic from adjacent multiple tracks, and weight limitations on adjacent cars in the same train.
4. Railroad bridge records.
(a) The organization responsible for the safety of a bridge should keep design, construction, maintenance and repair records readily accessible to permit the determination of safe loads. Having design or rating drawings and calculations that conform to the actual structure greatly simplifies the process of making accurate determinations of safe bridge loads. This provision is governed by § 237.33.
(b) Organizations acquiring railroad property should obtain original or usable copies of all bridge records and drawings, and protect or maintain knowledge of the location of the original records.
5. Specifications for design and rating of railroad bridges.
(a) The recommended specifications for the design and rating of bridges are those found in the Manual for Railway Engineering published by the American Railway Engineering and Maintenance-of-Way Association. These specifications incorporate recognized principles of structural design and analysis to provide for the safe and economic utilization of railroad bridges during their expected useful lives. These specifications are continually reviewed and revised by committees of competent engineers. Other specifications for design and rating, however, have been successfully used by some railroads and may continue to be suitable.
(b) A bridge can be rated for capacity according to current specifications regardless of the specification to which it was originally designed.
6. Periodic inspections of railroad bridges.
(a) Periodic bridge inspections by competent inspectors are necessary to determine whether a structure conforms to its design or rating condition and, if not, the degree of nonconformity. See § 237.101. Section 237.101(a) calls for every railroad bridge to be inspected at least once in each calendar year. Deterioration or damage may occur during the course of a year regardless of the level of traffic that passes over a bridge. Inspections at more frequent intervals may be required by the nature or condition of a structure or intensive traffic levels.
7. Underwater inspections of railroad bridges.
(a) Inspections of bridges should include measuring and recording the condition of substructure support at locations subject to erosion from moving water.
(b) Stream beds often are not visible to the inspector. Indirect measurements by sounding, probing, or any other appropriate means are necessary in these cases. A series of records of these readings will provide the best information in the event unexpected changes suddenly occur. Where such indirect measurements do not provide the necessary assurance of foundation integrity, diving inspections should be performed as prescribed by a competent engineer.
8. Seismic considerations.
(a) Owners of bridges should be aware of the risks posed by earthquakes in the areas in which their bridges are located. Precautions should be taken to protect the safety of trains and the public following an earthquake.
(b) Contingency plans for seismic events should be prepared in advance, taking into account the potential for seismic activity in an area.
(c) The predicted attenuation of ground motion varies considerably within the United States. Local ground motion attenuation values and the magnitude of an earthquake both influence the extent of the area affected by an earthquake. Regions with low frequency of seismic events produce less data from which to predict attenuation factors. That uncertainty should be considered when designating the area in which precautions should be taken following the first notice of an earthquake. In fact, earthquakes in such regions might propagate their effects over much wider areas than earthquakes of the same magnitude occurring in regions with frequent seismic activity.
9. Special inspections of railroad bridges.
Requirements for special inspections of railroad bridges are found in § 237.105.
10. Railroad bridge inspection records.
(a) The requirements for recording and reporting bridge inspections are found in § 237.109.
(b) Information from bridge inspection reports should be incorporated into a bridge management program to ensure that exceptions on the reports are corrected or accounted for. A series of inspection reports prepared over time should be maintained so as to provide a valuable record of trends and rates of degradation of bridge components. The reports should be structured to promote comprehensive inspections and effective communication between an inspector and an engineer who performs an analysis of a bridge.
(c) An inspection report should be comprehensible to a competent person without interpretation by the reporting inspector.
11. Railroad bridge inspectors and engineers.
(a) Bridge inspections should be performed by technicians whose training and experience enable them to detect and record indications of distress on a bridge. Inspectors should provide accurate measurements and other information about the condition of the bridge in enough detail so that an engineer can make a proper evaluation of the safety of the bridge. Qualifications of personnel are addressed in subpart C to part 237.
(b) Accurate information about the condition of a bridge should be evaluated by an engineer who is competent to determine the capacity of the bridge. The inspector and the evaluator often are not the same individual; therefore, the quality of the bridge evaluation depends on the quality of the communication between them. Review of inspection reports is addressed in § 237.111.
12. Scheduling inspections.
(a) A bridge management program should include a means to ensure that each bridge under the program is inspected at the frequency prescribed for that bridge by a competent engineer. Scheduling of bridge inspections is addressed in § 237.101.
(b) Bridge inspections should be scheduled from an accurate bridge inventory list that includes the due date of the next inspection.
13. Special considerations for railroad bridges.
Railroad bridges differ from other types of bridges in the types of loads they carry, in their modes of failure and indications of distress, and in their construction details and components. Proper inspection and analysis of railroad bridges require familiarity with the loads, details and indications of distress that are unique to this class of structure. Particular care should be taken that modifications to railroad bridges, including retrofits for protection against the effects of earthquakes, are suitable for the structure to which they are to be applied. Modifications should not adversely affect the serviceability of neither the bridge nor its accessibility for periodic or special inspection.
14. Railroad implementation of bridge safety programs.
FRA recommends that each track owner or other entity which is responsible for the integrity of bridges which support its track should comply with the intent of this regulation by adopting and implementing an effective and comprehensive program to ensure the safety of its bridges. The bridge safety program should incorporate the following essential elements, applied according to the configuration of the railroad and its bridges. The basis of the program should be in one comprehensive and coherent document which is available to all railroad personnel and other persons who are responsible for the application of any portion of the program. The program should include:
(a) Clearly defined roles and responsibilities of all persons who are designated or authorized to make determinations regarding the integrity of the track owner's bridges. The designations may be made by position or by individual;
(b) Provisions for a complete inventory of bridges that carry the owner's track, to include the following information on each bridge:
(1) A unique identifier, such as milepost location and a subdivision code;
(2) The location of the bridge by nearest town or station, and geographic coordinates;
(3) The name of the geographic features crossed by the bridge;
(4) The number of tracks on the bridge;
(5) The number of spans in the bridge;
(6) The lengths of the spans;
(7) Types of construction of:
(ii) Superstructure; and
(8) Overall length of the bridge;
(9) Dates of:
(ii) Major renovation; and
(iii) Strengthening; and
(10) Identification of entities responsible for maintenance of the bridge or its different components.
(c) Known capacity of its bridges as determined by rating by competent railroad bridge engineer or by design documents;
(d) Procedures for the control of movement of high, wide or heavy loads exceeding the nominal capacity of bridges;
(e) Instructions for the maintenance of permanent records of design, construction, modification, and repair;
(f) Railroad-specific procedures and standards for design and rating of bridges;
(g) Detailed bridge inspection policy, including:
(1) Inspector qualifications; including:
(i) Bridge experience or appropriate educational training;
(ii) Training on bridge inspection procedures; and
(iii) Training on Railroad Workplace Safety; and
(2) Type and frequency of inspection; including:
(i) Periodic (at least annually);
(iv) Seismic; and
(v) Cursory inspections of overhead bridges that are not the responsibility of the railroad;
(3) Inspection schedule for each bridge;
(4) Documentation of inspections; including:
(ii) Name of inspector;
(iii) Reporting Format; and
(iv) Coherence of information;
(5) Inspection Report Review Process;
(6) Record retention; and
(7) Tracking of critical deficiencies to resolution; and
(h) Provide for the protection of train operations following an inspection, noting a critical deficiency, repair, modification or adverse event and should include:
(1) A listing of qualifications of personnel permitted to authorize train operations following an adverse event; and
(2) Detailed internal program audit procedures to ensure compliance with the provisions of the program.