In 1955, there was a Modernisation Plan committed to wipe out steam locomotives on British Railways, and to replace it with diesel and electric locomotives which were proven cheaper and smoother to run. The last region to be wiped out was the Southern Region, and then there were a few 8Fs, Black 5s and Standard classes left in service. In August 1969, these last engines were withdrawn and every train on British Railways was either diesel or electric powered. However, many steam locomotives tried very hard to survive. The British Railway Network was becoming too modern for steam engines and they were all getting scrapped, but an engine named Oliver did not want to get scrapped, so he ran away with his autocoach Isabel, and a brake van called Toad. However, not very far from Barrow-in-Furness, he ran out of coal and had no more steam. So when Douglas had to shunt the midnight goods to a Barrow-in-Furness, he rescued Oliver and brought him to Crovan's Gate, the location of the NWR Workshops and the terminus of the Skarloey Railway. Once repaired, he became one of the main operating locomotives of the Arlesburgh Branchline of the North Western Railway. He also has another coach called Dulcie.
Oliver is the newest addition to the NWR's main fleet of engines having been introduce in Book 27 (Enterprising Engines) the third-to-last book before Wilbert Awdry's retirement from writing in 1972. This is also his only speaking role to date because he has appeared in Wilbert the Forest Engine and Henry and the Express without speaking roles. He has been introduced in Season 4 of the Television Series and since Season 6 seen a long absence until a brief return in Season 13.