The History Press, 2015, 164pp) [amazon.co.uk] documents the suspension bridges of John and Louis Harper, Aberdeenshire fence-makers turned bridge-builders.
Between 1870 and 1910, the Harpers designed and built over 40 suspension footbridges, mostly in the UK, but also as far afield as India, Nepal, Estonia, South Africa and the West Indies. Few survive now, and I've only visited one, at Newquay, although there are bridges built by the Aberdeen firm of James Abernethy in which Louis Harper may have had a hand, such as those at Aberlour and Cambus O'May.
Descendant of the Harper family, Douglas Harper, has been researching his family's engineering history for some time, with much of it documented on the Harper Bridges website. Now, this excellent book offers far more detail on the family firm's achievements, and I'd recommend it to anyone with an interest in historical suspension bridges.
The Harpers were innovators in their field: early users of steel wire rope; developers of a specialist wire-tensioning device; and users of pre-tensioned cables at deck level to greatly increase the stiffness of their designs.
The book gives a good history of the family, and their work both in fencing and then bridge-making, and puts this in context with a chapter exploring other suspension bridge developments in the 19th century.
The main part of the book offers detailed discussions of every bridge built by John Harper, and his son Louis. These are accompanied by numerous well-reproduced photographs and drawings, both present-day and archival. The level of research presented is remarkable.
What makes the book a particularly enjoyable read is the personal touch, as the author has attempted to visit as many of the bridges sites as he could, even where long-since demolished. In particular, the tale of his trip to Nepal turns the book from a simple historical record into a narrative which brings the past very much to life.
30 October 2015
13 October 2015
This is described as the longest estuarial bridge in Wales, and it's certainly the longest timber bridge in Britain, being a total of 731m long. It has carried the Cambrian coast railway across the mouth of the Mawddach Estuary, between Barmouth and Fairbourne, since 1867. There are 113 timber spans, comprising braced wooden trestles, and five metal truss spans at the northern end.
Originally, an opening span was included of so-called "cock-and-draw" construction, which reportedly took some 37 minutes for two men to open. This was replaced by Cleveland Bridge in 1900 with the present arrangement. The timber trestles have been entirely replaced at least once in their history, and were most recently refurbished by Network Rail the early 1980s.
The metal spans are an interesting arrangement. There are two bowstring trusses, which at first glance appear identical. However, one is a simply-supported span, and the other is a swing bridge supported from its centre on a pivot pier. Closer examination reveals that the swing span has vertical members above its pier which are not present on the other span, as you would expect, and I expect the detailed build-up of steel sections is also different.
The bridge has clearly not opened for some time (there's a photo of it open here). The opening mechanisms are in a state of considerable disrepair, and the rails across the bridge are now continuous across the span joints.
Only a single rail track passes over the bridge. The bulkhead rails are supported from longitudinal baulk timbers, which are held at the correct spacing by a series of metal struts and ties. Metal cleats hold the timbers in position on the main timber decking. On the metal spans, short lengths of longitudinal timber sit within "bath-tubs" in the metal bridge deck.
A toll was levied on the footway since the early twentieth century, but this has recently been abolished.
At the south end, the footway slopes steeply up to the nearby highway, and Barmouth residents have established a campaign for a better footway connection.
Meanwhile, the local council, which essentially "rents" the walkway from Network Rail for £30,000 per year, is under severe pressure to reduce costs and is considering closing the footpath. It's hard to argue that it should be more of a priority than many other hard-pressed council services, but unsurprisingly there is a great deal of opposition to closure, including an online petition with over 40,000 signatures.
I think this is a lovely bridge, of great engineering, historic and social value, and it would be a shame to see it closed or not maintained. It's not far from the site of Pont Briwet, another timber viaduct which, despite its Listed status, was recently demolished and replaced with a new concrete bridge. It would be a terrible shame for Barmouth Bridge to ever follow suit.
- Google maps / Bing maps
- British Listed Buildings
- Transport Heritage
- Engineering Timelines
- Timber railway viaducts in Wales
- Description of viaducts across the estuaries on the line of the Cambrian Railway (Conybeare, Proc. ICE, 1870-71) (and Discussion)
- British Railway Bridges and Viaducts (Smith, 1994)
- Civil Engineering Heritage: Wales and West Central England (Cragg, 1997)
- The Bridges of Wales (Breese, 2001)
- An Encyclopaedia of Britain's Bridges (McFetrich, 2010)
03 October 2015
This privately owned timber road bridge dates from 1880, when it was constructed by the Penmaenpool Bridge Company Limited, under agreement with the Barmouth Harbour Trust. It crosses the River Mawddach in Wales, and provides a useful short cut between the coastal towns of Barmouth and Fairbourne during its opening hours.
Most spans are 20-feet, but the central span is 30-feet. This span was designed for possible conversion into an opening bridge span, in case a disused boat-building yard upstream of the bridge was ever re-opened, but this was never required.
The structure is a series of straightforward braced timber trestles, with a heavy deck of diagonally arranged baulk timbers. It appears to be generally in good condition, although several of the deck timbers are loose.
The bridge is operated as a private toll bridge, with prices of 20p for a pedestrian, or 70p for a motor vehicle not exceeding 1.5 tonnes in weight. The bridge is only open between 8.30am and 6.30pm, with tolls being collected from the southern end, adjacent to the bridge-owner's cottage.