How is an AREMA bridge rating expressed?

An AREMA rating is expressed as a Cooper E number — the E loading a member can safely carry. E-80 or above means it is adequate for standard Cooper E-80 traffic.

What is the difference between Normal and Maximum AREMA ratings?

The Normal rating uses basic allowable stresses and reflects indefinite loading; the Maximum rating uses higher allowable stresses and reflects the maximum permissible load, giving a higher E rating.

AREMA Railroad Rating

AREMA Ch. 15 Preliminary estimate

Rate a railway bridge member as the Cooper E loading it can carry — Normal and Maximum levels, the rail-side analog of an AASHTO LRFR rating.

Results update as you type. These are educational estimates — confirm against the governing code and a licensed engineer before design use.

Method & references

An AREMA load rating expresses a member's capacity as the Cooper E loading it can safely carry (Manual for Railway Engineering, Chapter 15). Because Cooper loads scale linearly with the E number, the rating is the E value at which available capacity exactly equals the live-load-plus-impact effect:

E_rating = 80 · ( Capacity − DeadLoad ) / ( E-80 live effect · (1 + I) )

Two levels are reported, mirroring the AASHTO Inventory/Operating pair:

Normal rating — the loading the member can carry for an indefinite period, using basic allowable stresses.
Maximum rating — the maximum permissible loading, using higher allowable stresses (so it gives a higher E rating).

A rating of E-80 or above means the member is adequate for standard Cooper E-80 traffic; below E-80 indicates restriction, posting, or strengthening. Get the E-80 live-load effect from the Cooper E-80 tool and apply AREMA impact (Art. 1.3.5) either there or in the impact field here — not both.

Reference: AREMA Manual for Railway Engineering, Chapter 15 (rating provisions). AREMA rating is allowable-stress based; verify allowable stresses and impact against the governing manual.