OK time to admit I have a thing for steam trains. Gresley A4 'Pacifics' al-la Mallard world speed record holder, Stanier A4 Pacifics, but mainly Bulleid's A4 Merchant Navy, West Country, and Battle of Britain class Pacific class 4-6-2's. Unrebuilt over the rebuilt version. BR 71000 Duke of Gloucester rescued from Barry Scrapyard is a favourite. Nothing like a well turned out steam loco to stir the sole IMO! What's your favourite?