The other day I helped someone troubleshoot a Lionel 1122 switch that was buzzing and not operating. I don’t have time to take pictures or anything but hopefully this brief rundown will be helpful for someone.First, some background information: The Lionel 1122 and later switches are designed to switch automatically for an incoming train, because a train approaching the curved section of the switch when the switch is set straight will derail.
The buzzing generally is caused by a short circuit making the switch think a train is approaching when it isn’t.
This same procedure will aid in the troubleshooting of Lionel O22 switches as well as later non-derailing switches made by Lionel and K-Line.
First, remove the troublesome switch from the track. Connect two wires directly to the transformer, and touch one of the wires to any center rail. Touch the other wire to one of the outer rails of the curved leg. If the switch doesn’t snap, touch the wire to the other outer rail. The switch should operate. Whichever rail causes the switch to operate when touched with a wire needs an insulating O27 track pin, rather than a standard metal track pin. These pins, which used to be made of fiber but are now made of plastic, are available online and possibly from your local hobby shop.
Now that you’ve confirmed the curved leg works, repeat for the straight leg, and insert an insulating pin into that rail if one isn’t already present. If the switch operates on both legs in this fashion, the switch is operable and you just have a short circuit somewhere.
If the activating rails already had insulating pins and the switch still buzzes, you have a short circuit somewhere and you probably need to add more insulating pins. The center rail should never be insulated. But you may need to add insulating pins to several of the other rails. The easiest way to do this is to set up a simple loop on the floor with two switches, connect a transformer, put a locomotive on the track, and apply a little bit of power. If one or more switches still buzz, add insulating pins until the buzz goes away. This solution worked for us and got a layout that had two buzzing 1122s (out of three total) working again.