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Good Day O'Gauge Forum,

I am considering swapping out the switch motors on my Lionel 5165/5166 O-72 switches with O22 switch motors from my 1950's inventory.  The trouble I found with the O-72 switches they have under rated wiring insulation which causes them to short out under what should be normal operating conditions.  Has anyone attempted this swap, and if so, what issues, if any, did you experience.  Thank you.  Urbie

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Thank you for your suggestion.  Unfortunately, while inserting a new bulb in a 5166, I did so with the power on.  Unfortunately, I touched the bulb housing, the switch shorted out and no longer operates.  My parts guy who knows these switches said this is a common problem with the 5165/5166 switches.  They have unrated wire insulation, and are prone to shorts.  So I'm not sure rewiring the entire switch motor mechanism will solve the problem.

If an easier solution is to swap out the 5166 switch motor for a more reliable 022, then I believe that is the direction I would like to go.  So my question is what, if any, issues are there with a swap?  Urbie

I have 6 of these 5165/5166 switches on my layout, and all are powered by fixed voltage plugs.  The short circuit occurred only on the one 5166 that I was replacing the bulb...while the switch had the power on.  None of the other switches were affected.

But I have experienced similar issues at different times with some of the other 5165/5166's on my layout.  Very susceptible to shorts. when replacing the bulbs while the switch was powered up.  My suggestion is to make sure you turn off the power when attempting to replace a burned out bulb. 

Frankly, I'm not a big fan of these switches in that they are not the same quality as the O22's.  I am pleased to learn I can swap the switch motors on these with the O22's, and that should solve the problem. 

I had a 1990s vintage Lionel O72 switch, once.  Not only did the motor fail as yours did, but almost every loco that passed over it derailed, and some cars too!  I literally threw it in the trash.  Didn't want to sell it and foist that disappointment on anyone else in the hobby!

I'm pretty sure Ross makes an O72 switch with the identical footprint.  That's the way I would go!


The OP seems to be satisfied with his, with the exception of his concern for the motors.  Furthermore he's identified a reasonable approach to fixing what ails them.  Are you saying that he should throw them all out instead?

How about the rest of us that have them?  Perhaps we should too?  No thank you.  I'll stick with mine.  They work just fine for the toys that I run through them.

However, if I was into 3RS then it would probably be a different story ...


What I guess I'm trying to say is that they are known to be problematic, and in some cases probably not worth fixing.  When I bought my choices were a contemporary 5166, or find a prewar original.  This was 30 yrs ago, at the beginning of the "scale revolution."  This was before widespread internet penetration and the birth of a certain auction site.  No fasttrack, RealTrax and even Gargraves switches weren't great then.

If the OP gets it working, great, but if any of you see these online or on a table at a train show, I advise you to keep walking.  There are much better alternatives today, and the bitterness of poor quality is remembered long after the sweetness of a "bargain" wears off!

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