One of the more iconic symbols of Durham School is the large nameplate that stands in the Porter's Lodge near the entrance of the School. To paraphrase former teacher Jackie Marsden, the sign removes the school's rather coy anonymity; to a generation of Old Dunelmians it is as much a part of the school's identity as the badge, the Chapel, or the school song. Those younger may not have realised that the 'Durham School' to which the sign refers is not the site on Quarryheads Lane, but rather the name of a particular locomotive. 

The locomotive in question was one of Sir Nigel Gresley's V2 class, a series of highly successful mixed traffic locomotives built between 1936 and 1944. Of the 184 constructed, only 8 had names. The class leader was named 'Green Arrow' after the Anglo-Scottish good service they were designed to haul, while the rest were named either after regiments (The Snapper, The Green Howard, King's Own Yorkshire Light Infantry, Coldstreamer and The Durham Light Infantry) or public schools (St. Peter's School York and Durham School). LNER also approached the Royal Grammar School in Newcastle, but the Headmaster declined the offer. 

The L.N.E.R. No. 4831 was named 'Durham School' on the 15th June 1939 at the now defunct Elvet station in Durham. According to the programme, the band of the 8th battalion of the Durham Light Infantry played a programme of music which included selections of music from Gilbert & Sullivan's The Gondoliers and Noel Coward's Bitter Sweet, as well as Amoretta Tanze by Joseph Gung'l. Guests were "requested to face the nearest loud speaker in order to hear the speeches clearly". The first speech was given by Sir William Gray, the Director of the London & North Eastern Railway, with subsequent speeches being given by Mr R.A. Smeddle, the Darlington Locomotive Works Manager, and Mr C.M. Jenkin Jones, the Divisional General Manager. It was Smeddle who was responsible for the Locomotive being built. 

After this, the Head Boy of Durham School, Claude Gibb Ferguson, continued the ceremony by naming the Locomotive 'Durham School'. Three verses of Floreat Dunelmia were sung, whereupon the Locomotive Running Superintendent (C.M. Stedman) thanked Ferguson for naming the locomotive, and presented the Headmaster (the Reverend H.K. Luce) with the commemorative nameplate. In return, Canon Luce's daughter, Miss Jane Luce, presented the Driver R. Hodgson and the Fireman J. Breeze with suitably inscribed clocks. The Dean of Durham at the time, Cyril Alington, gave a speech; the National Anthem was sung; and then the Head Boy C.G. Ferguson drove the engine out of the station. Guests were entertained with tea at the school later. 

According to that year's Dunelmian, "the ceremony was effective and entertaining, and we are most grateful to the Railway Company for their kindness". The nameplate presented to Luce was a replica, which he would later hang in Big School. The ceremony was recorded by the BBC and was twice broadcast on the 'Stagshaw Searchlight'. This ceremony was the beginning of twenty-five years of active service for the train, during which time it would travel almost a million miles chiefly on the London-Scotland line. At some point the train was renamed '860' and then, after the nationalisation of the railway in 1948, '60860'. When the train was withdrawn from service in November 1962, it was sent to the Darlington Locomotive Works to be broken up. 

By coincidence, it was at about this time that the Durham School Railway Club visited the Darlington site. "Most of us had not previously seen the works in which several different jobs are done within one large area: the building of diesel shunting engines (0-5-0), the 'casual' and 'general' repair of main-line diesel and steam engines, and the scrapping of the older steam locomotives—a fate that is becoming more and more widespread these days". The trip took place in the narrow window of time before the train was scrapped in February 1963, and Assistant Master Denys Keeton, who organised the Railway Society, happened to spot the nameplate. Denys immediately began to negotiate its return, and it was eventually given back to the school by Mr Peter Johnson, the District Passenger Superintendent of British Railways. A short ceremony on the 23rd September 1963 in the Quadrangle saw Mr Johnson present Headmaster John Brett with the locomotive nameplate, which was then placed in the corner near the Porter's Lodge. 

In 1992 a painting was created showing the LNER Durham School Locomotive pulling an 'UP' Kings Cross Express across the Durham viaduct, with the iconic Cathedral and Castle found in the background. This was painted by John White, himself a Pooleite from 1960 to 1966. In more recent times, in late 1999, the introduction of a new headmaster and concerns about the security of the nameplate led to it being sold for around £21,000 to a private buyer. The act was and still is controversial; suffice to say that the current sign is the initial replica given to Alington back in 1939. The original nameplate was donated by the private collector to the National Railway Museum in York, where it can still be viewed.