Weekend Cinema - Forward to First Principals. 1966
A BTF (British Transport Film) Classic about what's happening on the lines during and after the changeover from Steam haulage to Diesel traction. Right, from the off; this is a Heavy Duty Rail Related Malarkey vid and (you should know by now) if it isn't your cup of tea you know the score; think Whacko, Really, it's only for hard-core users, admirers of the genre, and all interested parties but for everyone else you are strongly advised to go no further especially if you're a Tuk Tuk Merchant or a Tyre Kicker.
(keen eyed viewers will have noticed it's directed by Edgar Anstey the Doyen of Rail Related Documentary's of Note and the music bod is Muir Mathieson who went on to found the BBC Radiophonic Workshop.. ie Doctor Who stuff and similar).