Okay, figured it out.  The power attachment has to be pushed in to connect.  I can now use the nubs on the outside of the track.

I am a newbie setting up the Freight Master N-scale train.  The track to which I attach the power cord is curved and faces inward in my figure-eight layout.  This means that the power unit has to be inside the layout, meaning that I now have to find a way to run the power cord to the wall outlet without running it under or over the track.  The track to which I attach the power supply seems to have little "nubs" on both sides, but the nubs on the outside do not protrude far enough to make attachment on the outside possible.

Is there a way to get around this, or do I have to elevate the track at some point and run the power cord under it in order to reach the wall outlet?

Thanks.