Thanks for all the replies. Can I ask - how do you get notified of a response to your post? - I only noticed this by chance today, as I have yet another TTS Decoder problem, but seems like I generated a lot of dicussion. As a treat, my wife got me the Flying Scotsman R3736 Empire exhibition livery. Fitted an A1/A3 decoder and it worked fine until Saturday when it suddenly started jerking and stopped, though the sound was still there. Have replaced the analogue blanking plate and converted back to DC - I have an old R965 analogue controller and the Flying Scotsman came back to life, so assume there is a problem with the TTS decoder and not the loco itself.