Fetchwikidata: | coordinates |
Bridge Name: | Pont Briwet (1) |
Locale: | Penrhyndeudraeth, Gwynedd North Wales |
Carries: | Cambrian Coast railway and (toll) |
Builder: | Aberystwith and Welsh Coast Railway |
Heritage: | Grade II listed (formerly) |
Piers In Water: | 21 |
Open: | 1867 |
Closed: | 2013 |
Material2: | Wood, iron bracing |
Life: | rebuild GWR (1932) |
Crosses: | River Dwyryd |
Maint: | Network Rail |
Owner: | Private |
Length: | 140m (460feet) |
Height: | 4m (13feet) |
Width: | Standard gauge (4 foot 8½ inch) railway track 10feet roadway |
Load: | 2tonne (vehicles) |
Pont Briwet refers to the road and railway bridges that cross the River Dwyryd, near Penrhyndeudraeth, Gwynedd in North Wales. The first bridge was a Victorian road and railway viaduct that was constructed entirely from timber by the Cambrian Railways company.[1] Although it was recognised as being a Grade II listed structure, a result of it being an increasingly rare example of a surviving 19th-century wooden road and railway viaduct, the condition of the bridge had deteriorated over time and by the 21st century was posing regular and considerable inconvenience to both road and rail traffic.
Due to the operational impact of the old bridge, it was decided to build a replacement structure alongside as a joint project between the Welsh government and national rail infrastructure company Network Rail to upgrade the route. Despite plans to retain the old bridge for pedestrian traffic, it was determined that it had been further weakened and rendered structurally unsafe by the piling performed to establish the new bridge's foundations, resulting in its immediate closure in December 2013 and its demolition during the following year.
The new Pont Briwet crosses the Dwyryd on the same alignment as the original structure but it is both stronger and wider to accommodate larger vehicles and traffic volume. It also accommodates a combined cycle path and pedestrian walkway, as well as carrying multiple utilities, such as water and electricity, across its structure. Progress on the new bridge's construction was subject to several delays, the impact of which having been compounded by the necessity of the old structure's closure prior to its completion. It was initially opened only to rail traffic during September 2014; during July 2015, the new bridge was opened to road traffic as well.
The company's selected route, which became commonly known as the Cambrian Coast railway, is largely attributable to the civil engineer Benjamin Piercy, the company's chief engineer at the time. The selected route included the bridge now known as Pont Briwet, which was built to carry the line to the town of Porthmadog. During 1865, the Aberystwyth and Welsh Coast Railway company merged with the rival Cambrian Railways company. Shortly thereafter, boardroom struggles within the newly created company contributed to a delay in the project. Henry Conybeare briefly replaced Piercy as the company's chief engineer, before being himself replaced by Piercy's former deputy, George Owen. It is uncertain which of these were responsible for designing Pont Briwet.
During February 1866, the construction of the bridge was dealt a major setback when the contractor responsible for building it, Thomas Savin, was declared bankrupt. As a consequence, Pont Briwet was not completed until the following year, being officially opened on 10 October 1867.[2] The road over the bridge acted to remove an otherwise-necessary 13 kilometre (8 mile) detour via Maentwrog, a major boon to local residents.[3] The ferry service was soon closed due to it being unable to compete with the newly opened bridge.[2]
The piers of the bridge comprised either four or five timber piles, each roughly 350mm across, which were connected by crosshead timbers and braced with diagonals. Iron was used for the bolts and bracing bars used to fix elements in place. These created a series of frames on which longitudinal beams carried both the road and railway; those beams that were underneath the tracks were substantially larger than those under the roadway due to the greater weight of trains in comparison to road vehicles during that time.
A less popular practice of Pont Briwet was the toll that was in place for road vehicles.[3] During 1909, the local council lent its support towards efforts to abolish the tolls on the bridge; however, this pressure was ultimately unsuccessful at removing the tolls as the practice survived until the closure of the original bridge during the early 21st century. By 2009, toll prices were 40p for cars, as well as 30p for trailers and motorcycles.[3] Despite the nationalisation of the "Big Four" British railway companies during early 1947, the viaduct remained a privately owned toll road for road traffic travelling between Penrhyndeudraeth and Harlech. Over time, the roadway was redesigned to control vehicle movements using sets of traffic lights that were located at either end of the bridge.[4]
Reportedly, the bridge and line benefited heavily from the freight traffic generated after the establishment of Cooke's explosives factory near Penrhyndeudraeth during 1872.[2]
By 2010, a speed limit of 20mph had been imposed on all trains crossing the bridge. Additionally, in terms of road vehicles, the structure could only accommodate single-file traffic, serving both directions of traffic by alternating between the two.[4] It was also restricted to those vehicles that weighed less than 2tonne; as a result of this restriction, the route was only passable by cars, which meant that all heavier vehicles would have to go through a 8miles detour, significantly affecting the journeys of ambulances and buses, along with vans and lorries. Pedestrians were also unable to use the bridge because of the narrow width of the carriageway.[5]
Bridge Name: | Pont Briwet (2) |
Locale: | Penrhyndeudraeth, Gwynedd North Wales |
Carries: | Cambrian Coast railway |
Piers In Water: | 6 |
Open: | 2014 (rail) 2015 (road) |
Material2: | concrete, steel |
Replaces: | Victorian wooden viaduct |
Crosses: | River Dwyryd |
Width: | 18m (59feet) (completed) |
The new Pont Briwet would carry the single-track railway plus a two-lane carriageway and a 2.5m (08.2feet) combined cycleway and footpath. The road's speed limit would be raised to 40mph and toll charges abolished.[10] [11] Although the road and rail bridges share the same pillars, like the original viaduct, the superstructures of the new crossings would be separate. Planners also said that, apart from a four-week period in which work would be undertaken to relocate electrical cabling, the old viaduct would remain open throughout the works.[12]
The 'design and build' contract was awarded to Hochtief and Hewson Consulting acted as their lead consultant for the multi-disciplinary design team. The design of the replacement bridge features the extensive use of the innovative precasting technique which accelerated the construction activities and minimised the disruption to surrounding watercourse.