Does someone have a definitive list of stations where joining and splitting trains for different destinations still takes place? I know this happens at Machynlleth, Crianlarich, Haywards Heath and Salisbury (Exeter and Bristol portions), but I'm not sure about Faversham and Cambridge. And of course the Caledonian sleepers divide/join at Carstairs or Edinburgh. I'm not including stations where a unit is detached or added, e.g. at Nottingham on a Liverpool - Norwich service. Is there scope for extending this practice to give more through journey opportunities without adding more trains to a congested main line?