Following on from the thread on why slam-door trains were still built so late on at https://www.railforums.co.uk/threads/why-were-slam-door-trains-still-built-so-late-on.172064/, does anyone know why BR continued to build trains with tungsten interior lighting for so long after it had started to build some trains with fluorescent lighting?
For example, loco-hauled Mark 1s started to be built with fluorescent lighting from about 1959 onwards, albeit only in saloon coaches, and some DMUs and EMUs such as the Class 123s, 124s and 309s were built with fluorescent lighting in the saloons (not in the compartments, though). On the other hand, Southern Region 4-CIGs and 4-VEPs were still being built with tungsten lighting into the early 1970s!
For example, loco-hauled Mark 1s started to be built with fluorescent lighting from about 1959 onwards, albeit only in saloon coaches, and some DMUs and EMUs such as the Class 123s, 124s and 309s were built with fluorescent lighting in the saloons (not in the compartments, though). On the other hand, Southern Region 4-CIGs and 4-VEPs were still being built with tungsten lighting into the early 1970s!