Tuesday 26 May 2020

UIC Track & Structure sector publishes second edition of IRS 70778-2 “Carrying capacity and fatigue risks of existing metallic railway bridges”

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In June 2018 UIC published IRS 70778-2 “Recommendations for determining the carrying capacity and fatigue risks of existing metallic railway bridges” which included part of the content of the first edition of former leaflet 778-2 (July 1986).

After the IRS had been published in English, in September 2018 the UIC Panel of Structural Experts (PoSE) considered that the content of the document should also be made available in French and German to more experts. The UIC Track and Structure sector is therefore pleased to publish the second edition of 70778-2 in three languages, including editorial amendments of the English version.

The recommendations in this IRS are intended to be used for determining the load carrying capacity, serviceability and fatigue risks of existing wrought iron and steel bridges considering real traffic loading and the condition of the structure for:

  • Normal rail traffic on the standard track gauge European network for standard operational situations
  • The assessment of normal types of metallic bridges built with wrought iron, early steel and more modern steel under standard rail traffic loading

This IRS is not applicable to the design of new bridges. It uses a more precise safety concept without margins for future growth in the weight and speed of rail traffic that are included in the design requirements for new rail bridges.

IRS 70778-2 gives detailed information on the assessment of bridges, the material properties of different significant structural steels and various examples of fatigue sensitive/susceptible bridge details. Furthermore, it explains how to consider actions, load combinations and partial safety factors for the analysis of the ultimate limit state (ULS) and serviceability limit state (SLS) of bridges.

You can find the documents at ETF, the online shop for UIC’s technical railway publications, at the following links:

EN: https://bit.ly/2Tyazgn
FR: https://bit.ly/2ZuiNtG
DE: https://bit.ly/3e6Glc6

For further information please contact Harald Sattler, Senior Advisor Infrastructure:


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Fatigue susceptible detail