Hi Peter
I have a pic somewhere of the rail and trolley
A bit more info for anyone interested....if he logs in that is
It was an experiment to check the viability of the aircraft on schedule freight routes before committing to a full conversion programme
BEA was in a bit of a dilemma at the time as it had a fleet of Vanguard that were going to run out of work as the travellers wanted jets and they were desperate to get rid of the Argosy's as soon as possible
The forward air stairs were removed and the idea was more aircraft could be used with little mod (just a temp floor covering and the rail and trolley) and G-APEL could also be converted back to pax if needed....a sort of elastic fleet
From what I can tell though, G-APEL only flew freight at this time and no others did.
It paved the way for the full conversion to Merchantman which G-APEM was the fist and flew in 10th October 1969
About the same time Air Canada dedicated CF-TKK to pure freight
That however was stripped out and the windows blanked it was called the Cargoliner but did not have a freight door fitted.