Southernman46 asks what the class 15s sounded like. The Paxman engines were totally different to the English Electric and Sulzer-engined locos that frequented my home area. I spent many hours in the mid/late 1960s around my local railway when these (and the class 16s) were still running on trip freights and parcels workings. Memory may be playing tricks but I seem to recall they sounded like a Valenta-engined HST - obviously without so much volume and turbo-scream. I can recall them pulling out of Broxbourne after standing for a while and throwing out some black smoke as the power wound up. Sadly, I never blagged a cab ride in one, but a friend at that time became a secondman shortly before the 15s were withdrawn and he confirmed that the view was never particularly good in any direction. Their duties were, in the main, either lost or taken over by 20s and 31s, so no real contest in terms of reliability, crew comforts etc. Still, like them or not, the 15s and 16s provided some variety for us local spotters and they did have character.