If this is already known, apologies for the extra noise (also this is more 'generic' rather than 009 specifically).
While digging around the 'net looking for some data on a Hornby product, I came across this website that is literally a goldmine of information in the form of instruction sheets, service information and more of a wide variety of model railway manufacturers products, with quite a lot going back to early Hornby days.
https://www.hornbyinternationaluk.co.uk/?button=button2&servicesheets=none (https://www.hornbyinternationaluk.co.uk/?button=button2&servicesheets=none)