|Location Map ( geo)|
|Crossings related to the A487|
|Britannia Bridge (Porthmadog) • Dovey Bridge • Fishguard - Rosslare ferry • Pont Aberystwyth • Pont Llanychaiarn • Priory Bridge (Cardigan) • The Cob (Porthmadog)|
The Bridge at Maentwrog leads a strange sort of double life. For many years it carried the A487 across the Afon Dwyryd in the Vale of Ffestiniog, before being bypassed by a new bridge immediately upstream. The old bridge now carries the A496, but only the eastbound traffic, westbound traffic using the other arm of the former A487 along the south bank of the river.
The Old Bridge
The old bridge is loosely dated in the 1780s, due to its close similarities with the Pont Rhydlanfair, built in 1785 across the River Conwy. However, a precise date is not known. The bridge consists of three shallow stone arches spanning the wide channel, and carries a narrow roadway between stone parapets, with a noticeable hump in the middle. When this was still the A487, it must surely have had traffic signals to control the flow! Although both piers sit in water, when the river is low (and it is tidal to near here), only the southern arch seems to cross flowing water, the other two spanning pools in the riverbed.
With both piers standing in the river bed, and many conflicting currents due to the tidal nature of the river hereabouts, both piers are substantial affairs, with sizeable cutwaters on each side. These taper off towards the top of the arches which are surprisingly wide and shallow for a bridge of this age. The stonework above the arches, including the parapets, appears to be a slightly different colour to that between the arches, perhaps suggesting some reconstruction in the past.
The New Bridge
Sitting just upstream, the new bridge is a rather ordinary 3 span concrete beam structure. Again, only the southern 2 spans cross water when the river is low, the central pier standing on the river bank, but at high tide with a strong flow in the river it is a very different situation! The roadway is, obviously, much wider than before, carrying a two-lane road with wide pavements. However, and perhaps crucially, it is not wide enough to incorporate a turning lane for traffic turning into the A496. As much of the traffic on this road is turning right into it, and with the A487 curving across the bridge, this makes the junction somewhat difficult to negotiate when the roads are busy.
In amongst all of this, as already mentioned, there is also a busy junction, with the A496 meeting the A487. The junction once sat entirely on the south bank of the river, where the two arms of the A496 now reconverge - including the ability for traffic to turn right between the two to accommodate the house that sits here! The modern junction spans the river, with traffic from the A496 crossing the old bridge before reaching the A487, whilst traffic for the A496 has to use the road along the south side of the river, meaning much of it crosses the new bridge first. This slightly confusing set up has been chosen over the more common fully two-way triangle junction type due to the narrowness of the old bridge.
The A496 also continues eastwards to Ffestiniog, after a short multiplex with the A487, and so just a few hundred metres on, there is another T junction between the two routes, this time it is much less interesting however!