I regard the flickering Firebox as a gimmick which is probably just as well as, out of the 9 locomotives I have purchased with this feature over the past year, 4 of them have had the effect fail after around an hour of cumulitive running. Prince of Wales lost it's flicking firebox after around ten minutes running. I'm not returning them as it's a feature I'm not concerned about. I did mention it to SK before his retirement was announced. At that stage I had 6 locomotives with the feature of which 3 had lost the effect. He was going to get technical to phone me to discuss the issue, but they never did.