British Railway History Item
Crumlin Viaduct - GWR
Opened June 1st 1857 - Closed June 13th 1964 - Demolished 1965-1966
During the early - middle part of the nineteenth century the rush to exploit the vast coal reserves of the South Wales valleys was well underway.
The development of the railway network in the area played a vital part in this process. But the deep valleys and steep sided hillsides proved a formidable challenge to the railway engineers of the time.
By 1847 it became obvious that a new double track railway line of standard gauge was needed to link the N.A.H. (Newport, Abergavenny and Hereford) in the east, with the T.V.R. (Taff Vale Railway) in the west. Parliament authorized N.A.H. to build this line, which was to be called the T.V.E. (Taff Vale Extension).
This line had to cross the Ebbw and the smaller Kendon valley at Crumlin. It was decided that a stone bridge would be impracticable owing to the strong lateral forces of the wind in such a narrow valley. But the more likely reason for not opting for a masonry structure was because of the enormous cost involved. In August 1852 the Board of the N.A.H. invited tenders for the construction of a wrought iron bridge, by October they had received two. One was a lattice structure submitted by Doyne, who had previously designed on bridge over the river Taff at Treforest and the other by Kennard described as a Warren Bridge.
Charles Liddell the chief engineer with N.A.H. preferred Thomas Kennard's submission and this was accepted by the company. Kennard?s plan incorporated his own-patented modification of the Warren Truss (a form of bridge span invented by James Warren). There would be ten Trusses in total, each being 150 feet in length and supported by eight Piers. Six Piers and seven Trusses over the Ebbw valley, two Piers and three Trusses over the Kendon valley, with the hillside between forming a further natural support. Kennard himself designed the Piers, which were formed by 14 round cast iron columns, held in place by diagonal and horizontal wrought iron braces.
Kennard owned the Falkirk ironworks where the iron castings for the Viaduct were produced. Most if not all of the wrought iron was made at the nearby town of Blaenavon, by the Blaenavon Iron and Coal Company, which his father R. W. Kennard M. P. established.
Kennard had an assembly plant especially built at Crumlin called the "Crumlin Viaduct Works" where the various sections of ironwork was put together.
Work began on the Viaduct in the autumn of 1853 and the first pier was raised into place in December the same year. There was a ceremony to mark this occasion and it is reported that Lady Isabella Fiztmaurice the wife of M.P. and Chairman of the N.A.H. William Fiztmaurice buried an inscribe cup containing coins of the period into the base of the pier, which from then onwards was called the "Isabella" pier.
This was followed one year later by the lifting of the first Truss.
In April 1855 two men were killed and another one was seriously injured when a girder slipped and fell as it was being lifted into position dragging the men with it. The main structural work on the Viaduct was completed by December 1855, but it remained unopened for a further 18 months.
It was declared ready for testing in May 1857 and six locomotives loaded with lead and weighing 380 were run onto one of the spans, using both tracks. The resident engineer M. W. Carr startled the onlookers when he daringly climbed over the handrails to minutely examine the works for any movement.
The maximum deflection observed was between one inch and one inch and half. A few day later the inspector Colonel Wynne, passed the Viaduct as safe.
Lady Isabella Fitzmaurice on Whit Monday 1st of June 1857 eventually opened the Viaduct amid great celebrations. It was estimated that a crowd of 20,000 people travelled from all parts of the country to witness the event. Locomotives on the Viaduct line and the Western Valley line below were decorated with flags and evergreens. Over the centre of the Viaduct an Arch was constructed of evergreens and flowers with a banners declaring "Long life and prosperity to T. W. Kennard". Two cannon fire volleys throughout the day, which re-echoed from mountainside to mountainside.
The dimensions of the Viaduct were an overall length of 1658 feet; it was 200 feet high at the highest point above the valley floor.
An estimated 1,300 tons of Wrought Iron, 1,250 tons of Cast Iron, 800 cubic yards of Masonry for the Abutments and Foundations and 25,000 cubic feet of timber went into its construction
The final cost being ?62,000.
In the early years after it was opened there was some technical problems caused by metal expansion. This was particularly bad in the two hot summers of 1859 and 1865, which led to lateral movement of the track. This problem was finally solved when iron girders and wrought iron sheeting replaced the original wooden decking.
It then remained virtually unchanged until 1928, when because the more modern locomotives were very much heavier than their predecessors, it was decided on grounds of safety to replace the double track with a single one.
The railway line was closed down in 1964 and the last passenger train passed over the Viaduct on the 13th of June that same year. Demolition work began the following year, but this work was dogged with problems. Seven different demolition contractors were used in all before "Birds" were successful with the use of a Bailey bridge. Even while this work was in progress scenes for the film "Arabesque" which starred Sophia Loren and Gregory Peck were being shot on it.
Crumlin Viaduct remained the highest railway viaduct in Great Britain throughout its working life.
Contemporary Detailed description by Mr. Clayton, Architect
"The total height from the bed of the river to the level of the rails is 200 feet - being within 2 feet of the height of the London Monument: the piers, from centre to centre, 150 feet; actual bearing of girder, 148 feet; the total length of the viaduct 600 yards.
There are altogether ten spans or openings; but they are unequally divided by a tongue of land on which there are place masonry and earthworks, about 50 yards in length, making in reality, as far as the iron work is concerned, two separate viaducts.
The larger viaduct has seven spans and six piers; the smaller one three spans and two piers. The piers are formed of clusters of cast iron columns, placed in stages. Each column is 17 feet long by 1 foot in diameter; cast hollow, the thickness of metal varying from 1 inch to seven eighths, diminishing within, the same external diameter and form of column being preserved throughout.
The number of columns in each stage is fourteen and they are arranged on plan, in the longer direction, in four rows of three each, one with standing singly at each end of the piers, which gives it a salient angular outline. The width between columns at the base of the pier measures 13 feet 6 inches in every direction, taken on the square, excepting between the two centre rows, where it measures 6 feet throughout the height. The pier gradually diminishes to the top of the columns below the girders, where the dimension, 13 feet 6 inches, is reduced to 9 feet and at the external angle columns to 2 feet.
The dimensions of the piers at the base are, between the centre of the columns, 60 feet by 37 feet and the upper dimensions 30 feet by 18 feet, giving a diminution of 30 feet in one direction and of 9 feet in the other. To effect this, nearly all the columns are more or less inclined and the two centre are the only upright ones. The four columns at the corners, forming the square of the piers, lean diagonally, 4 feet 6 inches. The six intermediate columns correspond, but lean each in one direction only. The two single outside columns are most inclined, being 11 feet 6 inches out of perpendicular, forming a raking brace. The top of each stage of columns is connected by horizontal cast girders, 1 foot deep, with 5 inch flanges, bolted together. There are also horizontal and vertical wrought iron tie-rods. The former are circular and 2 inches in diameter and the latter flat bars four inches and three quarters. They are tightened with wedges where necessary.
The columns are fitted together with socket joints, a projection of half an inch being left on the top of the cap, which fits into the base of the columns above. These are held together by four ears cast on the top and bottom, which are fixed with bolts and nuts. The joints of the columns are turned fitted together with the greatest nicety to ensure a perfect bearing. The base platter upon which the columns stand vary from 3 feet to 6 feet in height and have a plate 3 feet square, resting on the masonry, into which they are joggled, plugged, bolted and put together with sulphur-joints. The number of stages of columns to the centre piers, it will be perceived, is ten, without base-plates.
The upper stages of the columns are connected together at the top by stronger horizontal girders than those below. They are finished with A-shaped or triangular bearers, placed over each row of columns, below which the girders rest. The foundations for the piers are formed of solid, flat-bedded and jointed masonry; they were generally carried down to the solid rock and vary from ten to three feet in depth. The girders, 150 feet long, are formed of wrought iron, after Kennard's patent. This consists of a stout beam and a bottom-tie below, with a diagonal filling-in, the whole being supported by the top beam on the principle of an inverted truss; the mode of execution, however, differs much. The whole girder is gradually strengthened by an additional thickness of plates towards the centre, given by a close calculation of the forces required to be resisted.
The bearing of the girder by which is sustained, is worthy of particular notice. It is held by the ends of the upper beam only, the lower one dropping in a state of suspension; the weight thus entirely rests on the last pin, which passes through the outside diagonal tie. The top of the angular termination of piers furnished with casting 3 feet 6 inches wide on the upper surface of which is a flat sinking three quarters of an inch deep. Under the ends of the upper bean are placed cast-iron blocks, hollowed out on the upper surface to receive half the diameter of the pin and of sufficient depth to raise the bottom flanges of the beam clear of the sliding groove.
The block has perfect freedom of play backwards and forwards, to suit the expansion and contraction of the girders as affected by the temperature of the atmosphere or the super incumbent weight. For this purpose a space of 9 inches is likewise left clear between the ends of the beams. The ordinary expansion and contraction in summer, between midday and midnight does not exceed a quarter of an inch. The girders have been tested with weight of 250 tons each, which produced a very slight deflection and, were the viaduct loaded with locomotives, this would far exceed any weight that could ever be put upon them.
The struts have also been tested with a crushing weight of 250 tons. The roadway is formed of 6 inch planking, bolted to the beams, the rails laid on strong, longitudinal- formed sleepers. An ornamental cast-iron balustrade is fixed on each side of the roadway.
The whole viaduct is not straight on the plan, the approaches to the larger one being curved, to which the last spans of the viaduct accommodate themselves by a slight inclination southwards at the extremities".
Gwyn Briwnant Jones And Denis Dunstone
Have written an excellent book about this line called "The Vale of Neath Line".
Additional information from - www.welshcoalmines.co.uk
Ordnance Survey Grid Reference - ST21339867
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Map Scale 10000 : Map Scale 25000
Last Updated : Saturday 30th August 2003 12:23