Connector track question

[fzorn]

I am setting up a model railroad for my son.  We currently have two connector tracks (rerailers).  The one that came with his initial set has a flat plastic plug which connects into the track on one end and a round single plug in to the power supply on the other.  The 2nd connector track we bought from a local retailer and has the flat connector for the track on one end, but the other end is a metal "U".  I am interested in connecting one connector track to the other.  I have not found any wiring that has the two plastic connectors to connect both ends to the track.  In fact, I can't even find the wiring sold separately from the track, so that I might splice it.  Suggestions?