i really can't guarantee anything, but i was on the railway for 43 years, (train driver retired) and from what i understand they kept all there records also it was a father to son job and a job for life so you could find them at a later date, the union was formed for drivers and firemen only (fireman was the line of promotion to driver you became a passed fireman and then driver, if you lived long enough, as you only got your job when a driver died, creating a vacancy, kali.
the address is:-9 arkwright rd, hampstead, london, nw3 6ab
tel. 020-7317-6406.
www.aslef.org.uk. email-
info@aslef.org.uk all the best, kali.