Thanks for that johnfilmer. those of us with longer memories of the former forum will no doubt remember the epic 'Slip Coaches' thread and the memorable contribution of the late PeterChall.
The advantage of this mode of working was the ability to get a coach (sometimes two), from a longer train to stop at a specific station whilst the main train continued on its way at line speed, negating the need to slow down, stop and then accelerate away again. The disadvantage was that the passengers were confined to the slip coach for that journey and also the receiving station needed to have a locomotive and staff available to deal with the now immobile rail vehicle occupying the line.
This might not be a problem at a larger station when railways were more expansive but as costs began to rise and efficiencies were sought, in the 1950's spare staff and locomotives became an expensive luxury.
The documentation gathered from the original forum thread hinted that the turn of the 20th century operations at places like Faversham the slip coach would be routed into a different platform than the preceding train requiring signals and points to be changed ahead of it. If so, then this must have required some very slick timing to prevent the coach being halted at a stop signal with consequential operational delay.
Never the less, and an interesting operation, the guard of the slip coach must have required a certain amount of skill to bring the detached slip coach to a smooth halt in the platform and not stop short. Also the detaching of the coach from a moving train and subsequent weight loss must have given the locomotive a short burst of acceleration in accordance with the laws of motion though whether this was noticeable probably depends on the overall weight of the train.
I have included below the original link to the last operation of a slip coach by British Railways in the 1950's from the 'Railway Roundabout' series. If this does not work just put the search term 'Slipcoach' into youtube.
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