Your cover article on the Leven Viaduct rebuild (NCE last week) describes the deck replacement of what is one of the UK's longest main line rail bridges.
Each of the 48 replacement spans is to consist of a single piece steel trough girder stiffened by longitudinal tee ribs beneath each of the two tracks to minimise the amount of prefabrication welding and the construction depth.
But direct fastening of the tracks to the deck is believed to be a first in the UK on a steel decked rail bridge of significant length.
Our concept and design was selected instead of the traditional longitudinal timbers as they are notorious for long-term maintenance problems.
Many rail bridge decks in the UK have been replaced in the past merely to eradicate longitudinal timbers by substituting ballasted track. At Leven the additional dead weight and construction depth was unacceptable because no increase of foundation loading or reduction of the headroom was possible.
Alan Hayward, Cass Hayward LLP, Chepstow, Monmouthshire NP16 5UW