Pottering down the M6 yesterday, near Dillicar Common, we were overhauled by two Class 325 units, which may have been the ones I saw at Motherwell earlier in the day. My driver asked me what the apparent blue LEDs on the side of them were (several, looked at about cant rail height, we both noticed them and I've no idea what it might be. Obviously not much time to look and it is just possible it was some line side stuff that looked as if it was on the train. Anyhow my mate isn't a rail buff and if I cannot answer this I'll have to turn in my ABC, crayons, Thermos and duffle bag. Thanks.