I just built a new layout, in case it matters, its gargraves 0-32 with a grade and lionel 022 switches and rcs tracks, dcs rev. L with 4.20, all powered by a z-4000 for track power and a pw zw for accessories and rcs/switch power, and a legacy set v1.3. I got my dcs engines running perfectly and pulled out my two legacy engines. The first was the 6-11208 big boy, it ran perfectly on my layout for an hour then as it went passed me I noticed it wasn't chuffing anymore. Upon further inspection I believe the engine and tender are not communicating, the engine starts up and responds to all legacy commands but the tender starts up in conventional (whistle and bell responds to z-4000 buttons) and has no chuffing. So I pulled out my other legacy engine the 6-11207 pennsy t-1, hooked the big boy tender to it and the tender functioned properly and it responded to legacy properly. The t-1 tender did not work on the bigboy so I figure it was the bigboy engine that is messed up, so I pulled the engine and tender off the track to work on them and hooked the t-1 to its tender and sent it on it's way, everything worked great on the t-1 for 2-3 laps around my track. Its now doing pretty much the same thing as the bigboy except there are a few points around the layout where it makes one or two chuffs and then its back to no response to legacy. I thought the draw bar may have been bent and the ir's may not be lining up, i bent and played with the draw bars over a dozen times and it doesn't change anything. I even pulled the ir's from the holders and stuck them lined up in a piece of heat shrink tubing (didn't shrink it on) and still have the same issue. I took the dcs system out and still have the same problem, took out legacy and still have no chuffing on either engines and now the t-1 isn't responding to the whistle/bell buttons on the z-4000.
Sorry to be so long winded but I am trying to cover anything that would be asked.