|Location Map ( geo)|
|Merionethshire • Caernarfonshire|
|free, formerly 40p (cars)|
|Crossings related to the Ffordd Arfordirol|
Pont Briwet (not to be confused with Barmouth Bridge) is a bridge near Porthmadog. It carries the single-track Cambrian railway side-by-side with an S2 minor road over the estuary of Afon Dwyryd. The road (a southward continuation of the A4085) cuts the corner when travelling from the A487 at Penrhyndeudraeth to the A496 for Harlech, shortening the journey by about eight miles.
The present 7-span concrete bridge was built in 2013-15 and replaces a previous wooden bridge of about 22 spans, which also carried both rail and road; however the previous road was generally only one lane wide, suitable for light vehicles only, and subject to a toll, though the toll was often not collected in later years.
The current bridge began construction in March 2013, and was opened to trains on 1 Sep 2014 and to road vehicles and pedestrians on 13 July 2015. The two transport modes are carried on two separate decks which sit on shared crossheads on concrete columns.
Construction began with the railway element of the new bridge, on the downstream side of the old bridge. Once the railway and various pipes and cables had been transferred to the new structure, the the old bridge was demolished and the road element of the new bridge built in its place. The old bridge was listed grade II and consent for its demolition had been obtained as part of the authorisation procedure for the new bridge.
Owing to a mixture of planned and unplanned factors on and around the site of the bridge, the railway was closed for over 8 months during construction, and the road for over 18 months. There appear to have been several reversals of policy on the question of whether or not to provide a temporary bridge during construction; in the event there was no temporary bridge.
For more details of the many vicissitudes of the construction period, see this forum thread.
Another combined road-rail bridge in the same area is Britannia Bridge (Porthmadog).