I have a 9 x 5 single oval loop of fastrack. Just learned the hard way that the supplied power wire is inadequate.
Could not figure out why my train was slowing down at the further end of the loop and then pick up speed as it went over the terminal track. Thought one of my tracks was defective or dirty.
I switched out the wire for a 16 gauge one and lo and behold immediately noticed the difference. The tricky part was finding the correct female disconnect that fit the fastrack connector. Had to use .110 version from my local auto parts store. All my local hardware and big box stores only had .250 way too big!!
George