The American Flyer track terminal, part# 690, is easy to install as long as it isn’t too bent up. Here’s how to install it properly, and how to fix it if you’re having trouble connecting it.
The track terminal has two clips that accept wires from the transformer, and a larger clip that engage the two rails of the track. Slide the shorter end of the clip onto the track, holding the terminal downward at about a 45-degree angle, then tilt the terminal upward. The longer end of the clip engages onto the track and snaps on tightly.
If the fit is too loose, bend the longer end of the clip slightly toward the track. If the fit is too tight, bend the longer end of the clip slightly away from the track.
Connect a wire from the clip marked “base post” to the terminal marked “base post” on the transformer. I prefer white wire for this connection. Connect a wire from the other clip to the variable post on the transformer. I prefer to use a red wire, or any other color besides green or white, for this connection. Here’s more on wiring the transformer if you need it.
Starting in the 1980s, K-Line and Lionel sold so-called “universal lockons” that work with either S gauge or O gauge track. This lockon works the same way as Gilbert’s #690 track terminal. Just ignore the extra clip toward the middle of the lockon. The extra clip is for O gauge track.
Using more than one American Flyer track terminal
For a smooth-running train, it’s best to use more than one American Flyer track terminal. Going by the book, you need a track terminal every fourth track section or so. When you install them, just make sure the terminals all face in the same direction, so the base post is always on the same rail, and use the same color convention for the wires to help you keep it straight.