MTH realtrax book or dvd

Hrspla

  Realtrax switches are non derailing, if you turn one over you will notice that the two center rails coming from the frog do not have brass contacts in them. From the top if you put a strait edge across the rails the inside rails should be slightly shorter making an air gap and electrically isolating the rails when connected to the next piece of track. When the train enters the switch opposite the direction the points are aligned the wheels bridge the isolated inside rail and the outer rail , completes the electrical circuit and aligns the points to the proper direction. You need to make certain the rails do not touch in these two places on any realtrax switch. See attachment

  What is probably occurring  on your set up with the siding connected, is that some of the inside rails are touching causing the switch to stay in one direction, or buzz if both are touching or a train enters from the other direction.  When you make the siding a dead end ,the gap opens and the  problem disappears.

  The solution is to align the track to maintain the air gap. Better  paint the ends with fingernail polish or put a small piece of electrical tape on each end. Best super glue a thin piece of plastic to the ends of the two inside rails and cut them to the rail profile, you will not need to worry about the gap closing and the rails  touching again. 

  Galon Tonell

Thank you Galon. I will give it a try and see what happens