Work began in March 2013 to replace the wooden Pont Briwet viaduct over the Afon Dwyryd near . The new bridge now carries two lanes of road traffic and the single track railway, and opened in 2015. It was hoped that, apart from a four-week period where power cables had to be moved, the old viaduct could remain open throughout the works. However, the bridge was found to have been affected by the piling work for the new bridge, and was declared structurally unsafe and closed in December 2013. This necessitated a diversion via Maentwrog for road users and caused rail services to terminate at . A new temporary bridge was due to open in Spring 2014, but this plan had been scrapped in favour of running a convoy system on the A496 road that serves as the diversionary route. Work then focused on completing the main railway and road bridge by the end of the year.