When I put Maerklin 37819, engine 051 013-1 on the roller stand yesterday, it wasn't recognized automatically by the Mobile Station. At all. Another locomotive was programmed just fine, so it wasn't the overall setup. Tonight I double-checked connectivity, checked the wires, checked the decoder socket, swapped in another decoder, nothing. I tried the decoder in the BR 50 with cabin tender and it worked there, so it wasn't the decoder (whew!) I slowly took apart 051 013 until I had the naked engine in front of me. I checked the cable connections, double-checked connectivity, put it on the roller stand. ... And it worked just fine. Slowly and carefully I put it back together, and ... it still runs just fine. Maybe user error and I didn't press Stop on the Mobile Station to let it detect the locomotive? But then it should have worked with the decoder from the other BR 50. I have no idea. At least now I know how to take this engine apart and put it back together. The fine ...