Carling’s slide collection is now available on our Virtual Archive.

Here at the Institution, we have recently finished cataloguing the papers of Denis Rock Carling, Superintendent of the Rugby Locomotive Testing Station (LTS). If you are interested in researching our Carling papers, or any other collections, please email us at archive@imeche.org Some of the images can be seen here.

In his Presidential Address to the Institution of Locomotive Engineers in 1927 and again in 1934, Sir Nigel Gresley expressed the desirability of the establishment of a national locomotive testing station. He envisaged that it would be used by British main line railways and the private locomotive building industry, he was Chief Mechanical Engineer to the London and North Eastern Railway (LNER) at the time. By 1930 a site on the outskirts of Leeds had been provisionally selected but appeals for Government funding were rejected for economic reasons. The Great Western Railway (GWR) already had a stationary testing plant of its own at Swindon (in operation from about 1905) but it apparently could not absorb the required power and capacity for a national service. In 1937 the London, Midland and Scottish Railway (LMS) and LNER decided to jointly build the LTS at Rugby. The, possibly apocryphal, story goes that Gresley and Sir William Stanier, Chief Mechanical Engineer of LMS, decided that the railway companies should join together to create a national testing station but that Charles Collett, Chief Mechanical Engineer of GWR, had secretly got his plant upgraded and subsequently when Gresley and Stanier visited to seek GWR involvement they were shown a locomotive running at full power. Hence, the venture excluded GWR.


Design inspiration came from a new plant at Vitry in France and an established one at Altoona in America. Specifications were issued during 1938, the contract for the test bed was given to Heenan & Froude. Work was well advanced when the Second World War meant it had to be suspended. Work resumed after the War and the Plant was officially opened in October 1948.

Having gained the Mechanical Sciences Tripos at Cambridge University in 1928, Carling went on to train at Beyer, Peacock and Company. During this time they delivered the 1930 Garratt’s to the LMS. In 1931 he took a sabbatical and visited most of the locomotive builders in Europe before returning to work. In 1936, Carling joined the LNER as Technical Assistant to the Chief Test Inspector, Chief Mechanical Engineers Department. He worked mainly in the Dynamometer Car Office on locomotive testing, with some work undertaken in Motive Power Department and in the workshops. When the War broke out Carling’s career took a very different course. In 1939 he went to work for the Admiralty in a technical capacity, working on magnetic mines and torpedoes. After the War, Carling was deeply involved in the transportation of chemicals out of Germany to Britain to be used in torpedo development. His papers show he was often in Germany and was stationed at Kiel. During this time Carling was a Lieutenant Commander, Royal Naval Volunteer Reserve. He also undertook work as an Admiralty Combined Intelligence Objectives Sub-Committee Investigator, in Germany. Carling was sent to visit Martin Diepen and his family in Dusseldorf for a technical interview and to recover records; he was also to visit Professor Paul Goerens but due to Goerens arrest (he committed suicide in custody) he had to see his wife, another visit was to the Director General of the Chemical Branch at Bad Oeynhausen. This intelligence gathering was crucial to the Allies understanding of the technical side of weapons development.

After the War, Carling was due to return to the LNER but owing to the unexpected death of DW Sandford, Carling was made the head of the Rugby Test Plant throughout its steam operations, 1948-1959. Swindon methods were adopted at Rugby. Swindon possibly had an advantage in that the same team carried out test work in the plant and also with real trains. In total, 26 different locomotives rode the rollers at Rugby. Ten or more were 4-6-0s and eight were 2-10-0s, mainly of the British Railway Class 9F types. In some cases the locomotive in question, notably Southern Railway (SR) Class ‘Merchant Navy’ 4-6-2 (original) and LMS ‘Duchess’ 4-6-2, were tested both between Skipton and Carlisle and on the Plant. By the early 1950s, mobile road testing had attained a high degree of sophistication and when steam locomotive testing ceased in the late 1950s data from stationary testing at Rugby could be satisfactorily reconciled with results from mobile testing. The last steam locomotive tests took place at Rugby in 1959 [some sources say steam testing continued until 1965]. Testing of diesel locomotives continued until 1965 but the station did not officially close until 1970. The building was demolished in 1984. The LTS, therefore, went from being cutting edge, to largely obsolete in little over a decade. In most cases a comprehensive report was prepared after testing and these were available to the public, the railways were nationalised at the time and so ownership was presumably felt to be communal.

Carling was considered an expert on 4-8-0 Tender Locomotives and his book on the topic was published in 1971, after many years of extensive research. Both at the LTS and in places throughout Europe he lectured about railways and testing, he was also an active and oft-published member of the Newcomen Society. His collection shows that in addition, he was an avid bird watcher and collector of coins! A different type of bird connection, Carling was in the dynamometer car for Gresley’s “Mallard” record beating 126 mph steam run.

Archive, Institution of Mechanical Engineers


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