We led a team in providing the detailed design for a 1.5km road and 800m rail improvement scheme which included a seven span viaduct using precast beams and crossheads, separate decks for the highway and railway. The 134m long fully integral viaduct does not have bearings or formal movement joints and is the longest structure of its type in the UK.

In addition, specialist track/structure interaction design avoided the use of expensive and difficult to maintain breather switches at either end of the rail bridge. The new track alignment also involved a rock armoured embankment and a replacement precast concrete station at Llandecwyn.

All the designs had to meet the highest environmental requirements of the Snowdonia National Park and resulted in Hewson winning the ICE Wales Award for Innovation.