American Flyer Transformer Wiring Diagram

Last Updated on February 18, 2019 by Dave Farquhar

A.C. Gilbert provided a wiring diagram with its train sets and transformers. But if your American Flyer transformer wiring diagram went missing after all these decades, not to worry. I have you covered. Here are some tips for American Flyer transformer hook up for the best possible operation while using as little wire as possible.

Gilbert was more consistent than some of its competitors when it came to its transformers. But some of Gilbert’s terminology may have made it so simple as to make it confusing.

Connecting an American Flyer transformer

American Flyer transformer wiring diagram
If you lost your American Flyer transformer wiring diagram, this should get you going again. This diagram is for 3-rail trains but the same principle works for American Flyer 2-rail S gauge as well.

The American Flyer transformer connects to track via a track terminal which locks onto the track. There are two wire connectors on the track terminal, and three on the transformer. The third connector on the transformer is for accessories.

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. By convention, the base post on the terminal is the outer rail on 2-rail track, and the center rail on 3-rail track.

Connect a wire from the other clip to the variable post, which is marked 7-15 volt, on the transformer. I prefer to use a red or black wire, or any other color besides green or white, for this connection. By convention, this post is the inner rail on 2-rail track, and the two outer rails (which are electrically connected) on 3-rail track.

If you don’t want to use a track terminal, you can solder wires directly to the track. This gives you a more robust connection.

The post marked 15 volt is for lights or accessories. Your accessories also have two posts for power, which can be confusing. The accessories share the base post with the track. Connect one wire between the base post on the transformer and one of the connectors on the accessory. I prefer to use white wire for this connection for consistency. Connect a wire from the other post on the accessory to the 15 volt post on the transformer. I prefer a different color for this wire, ideally a different color other than white or the color you use for track.

To lessen the current draw on your transformers for running trains, you can dedicate one smaller transformer to accessories. Phase it with your track transformers, then use the 15 volt post on the accessory transformer and leave the 7-15 volt post unconnected. Leave the 15 volt post on your track transformers unconnected.

An American Flyer 30b transformer costs over $200, so it can be cheaper to buy two 100-watt transformers, or 110-watt transformers and team them up with whatever you already have. Use the smallest transformer for accessories, and the two larger transformers for track. Most accessories draw 3-5 watts, so even a 25-watt transformer can power five accessories.

Hooking up multiple loops of track

If you have more than one train and loop of track, you can wire the base posts together to save wire. The trick is to phase your transformers first so they have the same polarity. Then the two base posts become interchangeable.

To save a lot of wire while providing maximum electrical consistency for smooth operation, run three loops of 14-gauge or 12-gauge wire underneath your table. One loop connects to your base posts. I like white for this connection. The other loops of wire are dedicated to each loop of track. Use black and a third color, such as red, for these connections. Then run feeder wires from your loop of wire up to every fourth track section on your layout above.

To connect your loops to the feeder wires or the transformer, use your favorite wire splicing method. I find soldering wires under a table cumbersome, so I prefer to use wire nuts or, better yet, lever terminal blocks. Cut into the wire loop, then strip about a half-inch of insulation off each end, and a half inch off your feeder wire. Then open three levers, insert each wire, then close the levers. I find this faster than using wire nuts, and it makes future changes to the wiring very quick and easy.

When you wire accessories, it’s probably overkill to dedicate a loop of wire to those. You can connect one post from the accessory to the nearest white wire, then connect all of the remaining accessory posts together and run one wire from the accessory nearest the transformer to the 15 volt post on the transformer.

Related questions

Can you use other transformers with American Flyer trains?

You can use an American Flyer transformer to power other makes of trains, such as Marx or Lionel, and vice versa. Gilbert and Marx used very similar voltages so they are a good match for each other. Lionel used a slightly higher voltage so go easy on the throttle when using a Lionel transformer with American Flyer trains.

American Flyer transformers don’t have the button to operate a Lionel whistle, and since their top voltage is 3-5 volts lower than Lionel, they won’t operate a Lionel train at full speed. But other than those two things, an American Flyer transformer still works with Lionel.

What size wire should you use with American Flyer trains?

If your layout is 8×8 or smaller, you can use 14-gauge wire between your transformer and track. For a layout larger than 8×8, you’ll want 12-gauge wire. Using wire that is too thin leads to overheating and voltage drop. If you want a smooth-running train, you’ll need to deal with voltage drop. Here’s how.

If you run loops of wire under your table like I describe above, you can use the heavier wire for the loops, and use 18-gauge wire between the loops and the track. Short lengths of 18 gauge wire at the end don’t cause the voltage to drop significantly.

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