Thanks Richard, but with respect, making a guess has a fair chance of being wrong.
Update: following a helpful phone chat with Rails I made the long drive over to them today. I took both the decoder and loco in the hope that they might demonstrate the fitted decoder in operation, unfortunately the decoder was taken ‘out back’ for testing and after around 10 mins it was brought back and declared in fine working order and I was ushered out (maybe I’m being a bit harsh but that’s what it felt like). I drove home, refitted the decoder, put it on the programming track and there’s no change, still no movement, no lights or sound!
So, where does that leave me? I have no reason to doubt that the decoder tested satisfactorily, the loco runs fine on DC and also with a different type of decoder fitted. My Trix controller works well with all the other decoders that I use (including V3.5 and V4 sound decoders) so I suspect it’s summat to do with the older controller software not communicating with the new V5 decoder, after all, the controller is the best part of 20 yrs old.
Last year I began thinking about getting a new controller and the only one that took my fancy was the SignaTrack device so, maybe I’ll take a closer look at it but in the meantime I’ll get a non sound decoder for the 37 to run it.
best regards and thanks for all the help, where would we be without RMweb?
PL.