(b) Operating railroad. The operating railroad that authorizes train movements over a bridge should take whatever steps are necessary to verify that the maintenance responsibility for the bridge is being fulfilled so as to safeguard trains operated under its authority. (c) Assignment of responsibility. The owner of the track carried by a bridge may assign responsibility for maintenance of the bridge to another party as long as the assignment ensures that responsibility for the safety of the bridge is not diminished. (a) Determination. The safe capacity of bridges should be determined by competent engineers using accepted principles of structural design and analysis. (b) Analysis. 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) Rating. 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. (a) Control of loads. The operating instructions for each railroad operating over bridges should include provisions to restrict the movement of cars and locomotives whose weight or configuration exceed the nominal capacity of the bridges. (b) Authority for exceptions. Equipment exceeding the nominal weight restriction on a bridge should be operated only under conditions determined by a competent engineer who has properly analyzed the stresses resulting from the proposed loads. (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. (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. (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. 4. Bridge records. 2. Capacity of bridges. 3. Bridge loads.
5. Specifications for design and rating.
(a) The recommended specifications for the design and rating of bridges are those found in the
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