Testing Testing!


Crumlin Viaduct seen circa 1960 shortly before closure. Photo: Ben Brooksbank.

New and repaired railway structures and equipment needed testing. These were tense times for those concerned. One early example was with the Crumlin Viaduct in Wales, west of Pontypool and spanning the Ebbw River valley. Work started in 1853 with Thomas William Kennard as engineer for the project. The viaduct, 200 feet high and 567 yards long, contained 1,300 tons of wrought iron, 1,250 tons of cast iron, 800 cubic yards of masonry and 25,000 cubic feet of Baltic timber. Construction was described as 150 feet long deck-type spans consisting of four pin-jointed riveted wrought iron Warren truss girders supported on piers made up of fourteen 12-inch diameter cast iron columns braced together. The last pier from Kennard’s Falkirk Ironworks was placed in position, and the last wrought-iron girder from the Blaenavon Iron Company was erected in December 1855. The viaduct, which had cost £62,000 to build, was therefore completed. However, it wasn’t until May 1857 that the viaduct was tested with six engines, additionally weighted with ingots, and a wagon containing old rails making a total weight of 380 tons. The test train was driven by a Pontypool driver called “Mad Jack”; he was the only volunteer for the job! He reputedly visited several public houses to take Dutch courage before the test runs. While he had been asked to drive very slowly for the first run, he actually drove very quickly, telling the terrified engineer, “When eternity looks you straight in the face, you may as well go at full speed to meet it!” But after repeated runs at varying speeds, the structure passed the test with 1¼ to 1½ inch maximum deflection and was declared safe by the Board of Trade’s Inspector. With line closures following the Beeching Report, Crumlin saw its last passenger train in 1964 and was demolished three years later.



The Royal Albert Bridge, Saltash, illuminated for its centenary in 1959. Photo: British Railways.

Similar testing took place with Isambard Kingdom Brunel’s Royal Albert Bridge over the River Tamar at Saltash linking Devon and Cornwall. Work on the pontoons started in 1854 and the two main spans were floated into position during 1857 and 1858. The piers and stone columns used 459,000 cubic feet of masonry, and 14,000 cubic feet of timber was used in the building. Brunel tested the single track broad gauge structure with a 1,190 ton load, and found that the two main 455 feet spans bent downwards by about seven inches each. The test load was almost three times heavier than any train running at the time. The tubes for the upper sections of the bridge’s main spans measured 16 feet 9 inches wide by 12 feet 6 inches high and each span contained 1,260 tons of wrought iron and 1,290 tons of cast iron. Prince Albert opened the bridge in May 1859. Brunel by now was in poor health and was taken over the bridge a few days later, four months before his death. The 17 approach spans were re-girdered in 1928, and in 1938 an army of men took almost a year to repaint the bridge using ten tons of paint and 200 gallons of coal tar on an estimated 39,000 square yards of structure. With the prospect of heavier freight loads, tests were conducted in 1966 to determine if trains of over 1,000 tons gross could be run. This resulted in work during 1969 to fit 24 new diagonal ties to each span, and over 160 years on the Royal Albert Bridge is still in daily use for passenger and freight services.



135 tons of “King” class number 6005 “King George II” after overhaul at Swindon Works in early 1962. Photo: Mike Peart.

Sunday 25th March 1934 was a successful test day for a new section of quadrupled track between Olton and Lapworth, near Solihull on the Great Western Railway’s Paddington to Birmingham main line. The new track to ease bottlenecks to allow a “two hour” London to Birmingham express passenger service included six new bridges. Four “King” class locomotives were brought in to test the work. One test performed twice involved the “Kings” coupled in pairs running at 2 mph to test deflection in the metal of the bridges. Then the four locomotives ran two abreast accelerating hard at 62 mph twice over each bridge, reversing after each run. Two ran “light engine” (on their own) and two had a two-coach engineer’s train. There were twelve runs in all and the locomotives used were numbers 6001 “King Edward VII” (recently fitted with a speedometer), 6005 “King George II”, 6014 “King Henry VII” and 6017 King Edward IV”. Each “King” weighs around 135 tons.


Mike Peart


Mike Peart is the co-author of Volumes 3 (Freight Marshalling Yards), 4 (Level Crossings) and 5 (Train Detection and Control) of the “History & Development of Railway Signalling in the British Isles” series, and Trains of Hope”, all published by The Friends of the National Railway Museum. He’s been an active Friend of the NRM since 1994 and was a founder member of the Great Western Society in 1961.







52 views0 comments