Fitch began his railway career in 1927 with the WAGR as a cadet. During this time he worked in the drawing office of the Way & Works branch as well as spending considerable time working in the countryside and at rural depots. The 1930s depression affected the WAGR and a large number of staff lost employment due to the lack of work. However, Fitch was transferred to Kalgoorlie in 1931 and took up the role of Engineering Assistant. Over the next thirteen years he worked around regional Western Australia before returning to Perth in 1944. Fitch spent the next four years as engineer in charge of design work for the Western Australian railway gauge standardisation report. In late 1947, Fitch gave a course of lectures on Railway Civil Engineering at the University of Western Australia and during this time proposed to the Faculty of Engineering that he would submit a thesis for the degree of Master of Engineering. His thesis was duly accepted and in 1949 he gained his Degree in Master of Engineering. In May 1949, Fitch left the WAGR after 22 years service and relocated with his family to Port Augusta in South Australia to commence work for the Commonwealth Railways. Fitch formally became the CR Chief Civil Engineer responsible for the Trans-Australian Railway, Central Australia Railway and the North Australia Railway. During 1951 and 1952, Fitch was a member of the Royal Commission into the route of the proposed new standard gauge railwayline from Port Augusta to Leigh Creek. It was during this time that the working relationship between Fitch and then CR Commissioner, PJ Hannaberry, began to break down. Fitch tendered his resignation on 8 February 1954 and was then appointed Assistant to the Railways Commissioner the South Australian Railways. Still with the SAR, Fitch's role and title changed in 1959 to Deputy Commissioner, essentially the same role but expanded to include stepping into the more senior role 'when the Railways Commissioner was ill, on leave or suspended from duty'. In late 1962 Thomas Playford, the Premier of South Australia, proposed that the narrow gauge line between Port Pirie and Cockburn on the New South Wales border be reconstructed to standard gauge. Playford approached the Commonwealth Government to provide funding for the project. On 19 April 1963, formal approval was granted and allowed construction work to commence immediately. There was, however, a slight change to the plan. Instead of converting the existing narrow gauge track to standard gauge, a new standard gauge railway line was built next to the former narrow gauge one. In 1966 Fitch became the SAR Railways Commissioner. The mammoth standard gauge project between Port Pirie and Broken Hill was completed in late 1969. The SAR planned to hold events at Port Pirie and Peterborough in recognition of those who worked on the project. Unfortunately these official opening events would be marred by a strike stop work of the Australian Federated Union of Locomotive Enginemen, and Fitch had no option but to cancel these events at short notice. During his tenure as Deputy Commissioner and Railways Commissioner for the SAR, Fitch was an important ally to the fledgling railway preservation scene in South Australia. In 1973, after 46 years of service, Fitch retired from the railways.
Retirement
After retiring from the railways, he moved to Kingscote, Kangaroo Island, with his wife for four years before returning to Adelaide. Fitch used his railway life and experience to become a respected railway author and historian, his three books Making Tracks, Railroading at its Wildest and Australian Railwayman were well received by rail enthusiasts and historians. On 29 October 2002, Fitch gained recognition when the University of New South Wales awarded him a PhD, making him the oldest person in the world, aged 92 years, to be granted such an award; confirmed by the Guinness World Records in March 2005. Fitch was inducted into the Engineers Australia South Australia Hall of Fame in 2008. In 2009 he was honoured by the National Railway Museum, Port Adelaide when the main display pavilion was named after him. He died on 20 July 2015.