railway enthusiast, then suggested recording using a model train, and a class-six engine and track was obtained from model manufacturer Basset-Lowke with that were set up in the film studio. Jackson proceeded to push the engine back and forth along the track at the same speed as the train in the picture which produced the sound they needed. Watt realised the importance of getting the sound right: "Without that sound, the centre of a film that was to make my career would have completely failed". During the construction of the sorting coach set, Watt, Jones, and Jackson were assigned an engine to themselves and travelled up and down Beattock Summit in Scotland several times. This included another dangerous shot captured by Jackson, after attempts to take footage of the driver's cab produced film that was too dark. To solve this, Jackson sat atop of the coal pile in the locomotive's tender while holding a reflective sheet made with silver paper that acted as a mirror to make subjects brighter. As he filmed, the train passed a bridge which knocked the reflector off and narrowly missed his head. The cameramen continued into Scotland to film the closing shots at dawn, and Watt captured the partridges, rabbits, and dogs at a Dumfries farm. During their stay in Glasgow, Grierson informed Watt that upon completing the interior scenes and recording the sound, the film's budget had been spent and suggested that filming cease. Watt still had more footage to capture, however, wishing for a coda that showed an engine being cleaned and serviced at the end of the journey before starting its next one. The situation was solved when the three stayed with Watt's mother in Edinburgh and travelled to Glasgow in the guard's van to get the final shots. Poem sequence After viewing a rough assembly of the film, Grierson, Wright, and Cavalcanti agreed that a new ending was needed. Wright recalled that it was most likely Grierson who noted that up to this point, the film had documented the "machinery" of delivering letters, but "What about the people who write them and the people who get them?" Grierson, influenced by Soviet director Sergei Eisenstein's use of montage and poetry in Old and New (1929) and Sentimental Romance (1930), thought a sequence with a spoken poem set to music would was deemed more suitable, and Auden was set the task of writing