The works staff and many at M&EE depots were in the engineering craft unions, particularly the skilled (Cat 4) staff. The AUEW were big for fitters, the EEPTU for electricians and plumbers (their unions merged in 1968) and the Boilermakers for smiths and welders. They all negotiated with BR through the “Confed” (Confederation of Engineering Unions) as one body.
Blue Asbestos finished for new build in BR workshops part way through the early Mk 2 build in 1966, which is why when I was at the Oak dealing with condo vehicles I had to send some for scrap rather than sell them on. Brown wasn’t much used anyway (mill board in DMU’s being where we most encountered it) and white was used thereafter in very small quantities in new build, mainly in heaters, until the early 1980’s. Very few vehicles on the National network now contain any asbestos and that is mostly the very small quantity of white mentioned above.
Asbestos in buildings is a right menace for anyone trying to do work involving drilling or disturbing any panels. Asbestos is fine if it is left alone and in good condition and fortunately there is not that much of it (compared to yesteryear) left about. NR, as owner of much of the railway “estate”, has to keep a register of all buildings that still contain it and anyone who leases assets off them has to know it’s there. It is being steadily eradicated as buildings are refurbished or demolished.