At 200 feet high and 1,638 feet long it was described as “one of the most significant examples of technological achievement during the Industrial Revolution”, but all that remains of Crumlin Viaduct, a victim of Dr Beeching’s axe, are its stone supports. It was the highest railway viaduct in Britain and only the Aqueduct of Spoleto in Italy and the Portage Timber Viaduct in the United States were taller. It was also the least expensive bridge for its size ever constructed.

In 1846 an Act of Parliament granted permission for the building of the Taff Vale extension which would allow the coal mines of South Wales to access the developing industrial centres in the North West and Midlands of England. Its route required the track to cross the Ebbw Valley, an engineering feat that needed to overcome two significant geological features; the valley was tall, creating a structural problem as well as a wind problem as it acted as a wind tunnel, and there were actually two valleys, the Ebbw and the smaller Kendon.

Concluding that stone would be a poor choice for a structure of this size and type, Chief Engineer, Charles Liddell, recommended that a cast iron structure be built. After a tender process, the contract was awarded to a Scottish civil engineer, Thomas Kennard, who cast the iron structures at his Falkirk Ironworks and shipped them to Newport. Construction began in October 1853.

The first girder was hoisted into place on December 3, 1854 but during the maneuvering of the second, it buckled, slipped, and fell. One man, who was standing on the girder at the time, was killed and two others seriously injured, remarkably the only serious casualty during the construction phase. Made of wrought iron with stone supports, the seven span section across the Ebbw was completed in August 1855 and the three span section across the Kendon in the December at a total cost of £62,000 or £41 7s a foot.

The viaduct was officially opened on Whit Monday, June 1, 1857, by Lady Isabella Fitzmaurice and the occasion was marked by celebrations. Trains travelling across the viaduct and along the Western line beneath were decorated with flags, flowers, and evergreens. To entertain the locals beer booths, fun fairs, and side shows were set up in the fields and a couple of balladeers sang a song they had composed to celebrate the event. “Thousands come from far and near,/ so full of youth and bloom,/ To open the Great Crumlin Bridge/ on the Glorious first of June” it went and copies of the song sheet were available at a penny a time. The first train to cross was greeted with “loud shouts and roars, accompanied by the roar of the cannons and music from the band; it made a most spirit stirring occasion”, a contemporary report noted.

Although the Crumlin Viaduct was listed in 1962 as a site of architectural and historical interest, British Railways was allowed to demolish it after passenger services had stopped using it and because it was thought to be structurally unsound. The last passenger train to cross it was the 21.10 from Pontypool to Treherbert on June 13, 1964. Demolition began in the summer of 1966. Curiously, while the work was being carried out, the viaduct was used as a set for the film Arabesque, starring Gregory Peck and Sophia Loren.