did u try testing on a separate circle of the track to eliminate your possible track causing the problems and did you also try a factory reset on said engines . if that does not show anything I would try another TIU so you'll know it's not the tiu but engines seems odd that so many engines are having the same problem! I would think either a track problem or dcs remote or tiu issue. you need to confirm what's causing it and then go from there! your getting 10 tens all throughout the lay?
alan
