I have a MTH 20-3135-1 Santa Fe Hudson. I went to run the locomotive today and as it went around a curve it lost control, accelerating to full speed with the lights flickering. When it hit the straightaway after the curve it went right back to its previously set speed. Same thing happened when it hit the next curve. I stopped the locomotive, turned it around, and ran it in the other direction. It worked fine. I started jiggling the tether and sure enough that caused the locomotive to lose the DCS signal and accelerate to full speed with the lights flickering. I decided at this point to pick up a replacement tether at my LHS. I replaced the tether and all went back to normal and the locomotive operates perfectly again.
So my question is how did the tether go bad? I bought the locomotive this past August. It was basically MIB and had 15 scale miles and an hour of run time. It has run perfectly till today. The only time I disconnected the tether since I first put the locomotive on my layout was about 3 months ago when I replaced the battery with a BCR, so it's not like I'm constantly disconnecting the tether. The locomotive is rated to run on 042 curves and I haven't run it on anything less. Could it have just been a bad connection from the factory or is there anything that could have caused the issue?