Now, to the OP comment;
Many people do not connect and disconnect Realtrax properly, MTH has not put out instructions and this is the problem.
Hold the Track in a V with the rails touching. (about 45 degrees)
Rotate the track flat while pressing the rails together. This makes the electrical contacts align properly. Pushing them in straight like a pinned track can cause side to side shifting while connecting and then the contacts can slip past each other.
Add the next piece by holding it up at 45 degrees and pressing the rails together as you bring it down flat.
Last connection of a loop, hold both sides up in a shallow V and press together.
The larger the loop the easier this gets.
To disconnect, hold one piece flat and raise the next one, they will separate smoothly.