DIFFICULT decisions regarding fleet maintenance and infrastructure renewals based on cost continue to be made by Transport for London, despite an announcement last December that it would successfully balance its 2023/24 budget.
One example is the London Underground S-Stock fleet, used across the sub-surface railway. The S7 fleet, formed of seven cars, is used on the Circle, District and Hammersmith & City Lines, while the S8 fleet, formed of eight cars, is used solely on the Metropolitan Line.
The S8s were delivered first, entering passenger service in July 2010, with the initial S7s introduced on the District Line, just under two years later in June 2012. On average, the S7 units are approximately three to four years younger than the S8 trains, which is reflected in failure rates, with S7…
