# How To: Get your 1121 Switch to auto-switch



## erkenbrand (Dec 6, 2010)

I've read about this elsewhere, and saw a Lionel article on it, and decided to do it in my layout. After a couple of unfortunate incidents, I came to recognize the value of a switch that will automatically correct itself for an oncoming train.

The process is actually pretty simple. You just have to be willing to pull apart a couple of pieces of track and play with a soldering iron. 

1. At your switch, pull the incoming track segments. From each you'll want to take off one of the outer rails. I picked the rails that would allow for the shortest wire run to the switch.

The rails are easily removed, just use a screwdriver / pair of pliers to pry up the tabs holding them down.

2. Once removed you need to find something that will totally isolate the rails from the ties. You want to replicate what Lionel or whoever made your track did to the center rail. I used the ends from a box of shotgun shells, but pretty much any thin cardboard should work.

I pulled apart an old piece of track and used the isolator from Lionel as the template for the correct size to cut the ones for my track.

Make three for each track, then put them in place and bend the tabs back down to hold the rail in place.










3. Once the rail is back in place, you'll need to solder a wire to it. This wire will run from the rail to the correct pin on the switch. I made sure my wire was long enough to run hide beneath the switch. 

Just solder the wire to the bottom of the rail nicely out of sight.










4. Now, on each end of that isolated rail you need to insert the plastic isolator pins you can find at your local train shop / online. Make sure you get the ones for O27 rail, the ones for O rail are too big to fit.

5. Go ahead and put the rail sections back into your layout, and connect them to the switch. 










6. Run the wire leads to the posts on the switch. Make sure you run the correct wire to the correct post! If you get them backwards this whole process won't do you any good. 

Apply power to the track, and use a jumper wire to jump from the isolated outer rail to the non-isolated outer rail. This will trigger the switch and now you'll know which post your connected too. Got it wrong? Just reverse the wires. It only takes a second.










You're all set! Now, on to the next one.


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## gunrunnerjohn (Nov 10, 2010)

Great idea and well presented! 

If you're lazy, there are insulated track sections available that accomplish the same thing without the shotgun shells being available.


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## tjcruiser (Jan 10, 2010)

Erk,

Excellent how-to with very clear, simple to understand photos and explanations. Well done.

TJ


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## Big Ed (Jun 16, 2009)

Is your cover on right for the switch?

It looks like the tabs are on top of the switch?

Good idea thanks for sharing.:thumbsup:


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## gunrunnerjohn (Nov 10, 2010)

big ed said:


> Is your cover on right for the switch?
> 
> It looks like the tabs are on top of the switch?
> 
> Good idea thanks for sharing.:thumbsup:


I don't think it's possible to put the cover on a 1121 switch on incorrectly, they only fit one way.


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## Big Ed (Jun 16, 2009)

gunrunnerjohn said:


> I don't think it's possible to put the cover on a 1121 switch on incorrectly, they only fit one way.



I guess it is right.
You can put the cover on without the tabs being set in the notches but then the cover would be raised slightly. (I did it once )
His cover looks flush with the base.


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## erkenbrand (Dec 6, 2010)

I think it's the way the flash reflected. It does make it look like the tabs are outside the base. I went and checked and can confirm they are in correctly. 

Thanks for noticing!


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## gunrunnerjohn (Nov 10, 2010)

I might have to make you a great deal on a pair of these same switches I have on my shelf, I'll never use them.


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## erkenbrand (Dec 6, 2010)

I really like those switches. They function well, but I really like the way they look.

So, my ears are open, and the wallet could follow. 

I'm also trying to find some of the controllers. . . 

All of my Marx switches are moving to a layout that I'll be building in my woodshop. I checked the other day and discovered I have two boxes full of O27 track. More than enough for my shop setup.


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## gunrunnerjohn (Nov 10, 2010)

I have the controller, and I may have another old one that you could "refurb", let's check...

I have a controller with wires that "appear" to be pretty pliable, and also two that need wiring and cleaning up. Hard to believe they wouldn't work, since they're dirt simple inside. 

Drop me a PM and I'll make you a deal you can't refuse.


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## erkenbrand (Dec 6, 2010)

Here's an interesting adendum . . . what happens when you have a switch leading directly into another switch?

You can get the auto switching to work. But not completely, at least not in a way I've figured. I'm trying to do this without pulling the switch apart and isolating the rail that way. But I think that will be the end result to make it work right.

For now it all works except for the incoming track on the small loop does not auto trigger the second switch.


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## gunrunnerjohn (Nov 10, 2010)

You're not supposed to put switches that close, they'll get together and multiply and you'll have no regular track left!


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## erkenbrand (Dec 6, 2010)

I'm hoping the isolation pins help with prevention. We've been discussing switch family planning.


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## gunrunnerjohn (Nov 10, 2010)

Well, I can see it's a problem, because there's too more on their way to you now.


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## T-Man (May 16, 2008)

Just run another set of wires, from the small loop detector rail, or the first switch, to the second switch. so both will operate from one pass.


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## erkenbrand (Dec 6, 2010)

Here's the problem:

When Switch 1 is auto switched to pass straight, Switch 2 needs to kick to the right. I have that wired up. So, Switch 1 post A is tied to Switch 2 post B.

When Switch 1 is auto switched to the right, Switch 2 still needs to kick to the right. That would mean Switch 1 post B would be tied to Switch 2 post B. 

Since that would then connect Switch 1 posts A and B together in the circuit, it causes a short.

The end result is that there's only 1 circumstance in which Switch 2 won't auto-switch. 

Make sense?


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## servoguy (Jul 10, 2010)

Marx used to make a simple device to accomplish what you are trying to do here. They had a piece of thin copper that clipped over the rail. It had insulation inside of it. You could make one of these from brass or copper and some electrician's tape. It doesn't need to be more than half an inch to an inch long. Clip in on the outside rail (either one) of the appropriate switch and wire it to the terminals.
BB


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## gunrunnerjohn (Nov 10, 2010)

I have one of those in my junkbox, wondered who made it.  It's about 4" long. Too bad I didn't know you had the need, I'd have tossed that in the box with the switches.


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## erkenbrand (Dec 6, 2010)

Hmm, time to get creative with some copper.


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## erkenbrand (Dec 6, 2010)

I think I found the answer after some intensive research. It's the magnetic reed switch. I've seen where they're being used in HO layouts, so with a little tweaking it should work in my layout too.

Now, I just have to have the patience to wait for the order from Digi-Key.


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## gunrunnerjohn (Nov 10, 2010)

Remember, the reed switch will NOT handle the kind of currents and voltage spikes from switching, I think you'll need a relay to handle the load.


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## erkenbrand (Dec 6, 2010)

I have relays, so that's not a problem. This should be interesting, I've never used these reed switches before.


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## servoguy (Jul 10, 2010)

If you use AC to power the relays, make sure they are AC relays. You will also want to put a transient voltage suppressor across an AC relay and a diode across a DC relay. 

You could also use a triac which will draw less current from the reed switch and is not inductive.

BB


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## T-Man (May 16, 2008)

You still can do it your way. Just add another isolated section.











I guessed at the connections but you get the idea.
Reed switches are cool.


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## gunrunnerjohn (Nov 10, 2010)

Getting complicated around the switches!


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## servoguy (Jul 10, 2010)

Just remember not to leave the train sitting on the insulated track sections with the E unit in neutral and the power on. You may smoke the coils in the switches.

BB


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## erkenbrand (Dec 6, 2010)

Yup, I had started to take T-Man's path a couple of days ago, but decided against it at the time. Tonight, I'm planning on isolating that whole section of track so I can use it as a parking area for my trains heading to the factories there, while the passenger and other trains travel the main outer loop. 

So, I might just go ahead and do it tonight since I'll be killing the power to that track segment when not in use.

Yup, it's definitely getting complicated around the switches! All for that one last direction that isn't auto-switching.


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## gunrunnerjohn (Nov 10, 2010)

Makes you wish you went for O31 and 022 switches, it's built-in.


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## servoguy (Jul 10, 2010)

erkenbrand, remember that the non-derail feature works even with the power disconnected from the inner loop. As long as the switch on the outer loop is powered, the non-derail feature works.
BB


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## Big Ed (Jun 16, 2009)

I don't have any problems with mine.

When I want to use a switch 
I push the lever on the controller and it switches.

You ought to fire the switch man if he forgets.


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## T-Man (May 16, 2008)

When you isolate the branch line all you need to do is the center rail.
Bruce's two statements make sense. As far as the switches go, Two can be lined up, But you need that extra isolated rail up the line. You can modify one piece of track to have two isolated sections on on side, Cut the track add an insulated pin and add a extra tie for support.


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## erkenbrand (Dec 6, 2010)

I like the idea of cutting the track to have the two isolated sections on one side. Thanks! That hadn't occurred to me and fits in perfectly with what I want to do.


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## gunrunnerjohn (Nov 10, 2010)

You can also use two half track pieces and isolate them, no need for any cutting.


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## servoguy (Jul 10, 2010)

The O-31 half track sections are not exactly half of a full length section. I don't know about the O-27 half track sections. It might be better to cut a full section so the track geometry is correct. I just looked in the Lionel catalog, and the length of the track sections is not given.

BB


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## gunrunnerjohn (Nov 10, 2010)

Hmm... good point. They're 5.5" long. The O27 ones are 4.75" long. Neither of these sizes make a lot of sense now that you mention it.


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## T-Man (May 16, 2008)

I am glad you guys have them. All I have is standard lengths, I cut the rest.


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## gunrunnerjohn (Nov 10, 2010)

I got these with other track purchases, every time I've actually needed a short piece, I end up cutting as well.


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## servoguy (Jul 10, 2010)

I think what Lionel did was make the tie spacing on the half sections the same as the tie spacing on the full sections. This may have been done so the machine that crimps the ties could be used for both full and half sections. 

I cut them with a cut off wheel in my Dremel. I only cut the tube and then bend the rails to break the flange. Quick and easy.

BB


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## gunrunnerjohn (Nov 10, 2010)

My Dremel tool gets used every day. I actually have three of them, two Dremel and a cheap $20 clone. I actually bought the second Dremel when the first one bit the dust, then I located the parts to make it whole again, so I have an embarrassment of riches.


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## erkenbrand (Dec 6, 2010)

Well, I have you there. 

I have four Dremels - two with cords, two with batteries. I will say - don't bother getting the ones with batteries. I bought my second corded Dremel because I got tired of the dead batteries. 

I haven't gotten any further with the updated switching. Once my new switches from Gunrunnerjohn show up I'll get back to it. I have a 1121 that I found at Goodwill and is in really sad shape. Currently, it's in use, but I really need to pull it and restore it. 

Once I get it working right I'll get back to the auto-switching challenge.

One note: I had a thought this weekend that I'll try first. I'm going to pick up a lever activated micro-switch and use it first. I've had a lot of success using them in other projects that have similar power requirements.


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## gunrunnerjohn (Nov 10, 2010)

I didn't even consider the ones with batteries. I know that many tasks with the Dremel take power, and my track record with battery stuff is pretty poor. 

You should have those switches today I would imagine, they went Priority last week, I think Thursday.


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## erkenbrand (Dec 6, 2010)

Thanks again for the great deal on the switches! And the controllers. 

Currently, I'm running around the track with a jumper wire in hand to switch stuff around, and that gets to be a pain pretty quickly. 

The lenses and lamp sockets showed up Saturday. The log loader is looking good, and the old Goodwill 1121 is looking much better. After a little restoration work on each, I'll be able to move on to more refinement to the terrain.


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## overlander (Dec 24, 2010)

Interesting idea , all this , but I like throwing the switches . Pushing the lever and hearing that clack sound the switch makes pleases me greatly for some reason . I cut my track with a tiny hacksaw from Home Depot . I cut a three inch piece of wood on a radial arm saw , making three slots in it . I put the rails in the slots and clamp the whole thing in a vice and with a light touch , saw right through the rails , one at a time . I tried the Dremel , or in my case Foredom tool but it seemed to eat up the fibreglass wheels quickly . Do you guys use some other cutting tool in your Dremmels ? Cliff


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## T-Man (May 16, 2008)

I got a Sears cutting kit, that has larger fiberglass wheels. They last longer. They must be 1 /14 conpare to the very breakable thin 3/4.


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## gunrunnerjohn (Nov 10, 2010)

I don't ever use the tiny ceramic wheels, I buy the larger fiber reinforced wheels, they last a long time before I wear them down enough to replace them. I buy them in 100 piece lots from Widget Supply. If you buy the ones with the 1/8" hole and the matching arbors, they're also a bit more robust.


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## erkenbrand (Dec 6, 2010)

Throwing the switches is a large part of what makes them fun. The auto-switching is a safety measure for me. Sometimes a switch will be thrown and I'm distracted. . . and then there's a derailment and crisis on the layout. 

I'll have to try those cut-off wheels from Sears. I've been using the regular Dremel ones and they do get eaten up pretty quickly.


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## gunrunnerjohn (Nov 10, 2010)

Like I said, don't go to Sears, they're EXPENSIVE there!. Try this for a decent price: http://www.widgetsupply.com/page/WS/PROD/dremel-cut-off-fiberglass-wheel/BBH20


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## overlander (Dec 24, 2010)

Erkenbrand , are you saying that you can still use the switches manually with this set-up ? If so , that would be great . I remember my first day with my new engine . I missed a switch and it derailed . Plop ! Right down on the concrete basement floor . Over a four foot drop .Now I have plexiglass at all my switches near the edge . I just didn't think it looked there were two sets of wires in the pics , and wouldn't there have to be ? Thanks for the cut-off info guys ! Cliff


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## servoguy (Jul 10, 2010)

You can use a manual controller with a switch that has the non derail feature wired also. Just don't try to throw the switch manually when the train is sitting on the non-derail track section.
BB


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## erkenbrand (Dec 6, 2010)

Yup, you can still manually switch everything. The auto-switching only occurs on one side of the switch to prevent derailment. Everything else is still manual. And in some places I can't do it at all because I need to be able to choose the rail I want the train to take and setting it up for auto would remove that ability.

I build guardrails around my layout for exactly the same reason. One day the train hit a switch that was in the wrong position, derailed and fell 4' to the concrete floor.

It does take some extra wires to get the auto switching working. But those are only on the affected switches. Once I get done with the last auto-switch I'll do another photo set of each one so you can see how it's laid out.


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## overlander (Dec 24, 2010)

Erkenbrand , that would be great . I'll look forward to seeing that . Servoguy , what would be the result of of throwing that switch manually when the train is on the non-derail track . Just won't work ? Or overpower the coil ? Cliff


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## gunrunnerjohn (Nov 10, 2010)

Since O27 switches have the coil energized whenever the non-derailing track section is energized, you'd be trying to have both coils pull the switch. Suffice to say it wouldn't have the desired effect.


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## servoguy (Jul 10, 2010)

I remind everyone again that if you leave the coil energized in an 1122 or 1121 switch, you may release the smoke and then it won't work. Remember, electronics runs on smoke and when the smoke escapes, they don't work any more. 

Bob Nelson has a good cap discharge circuit for O-27 switches which I recommend you install if you have a non-derailing feature implemented. Bob's circuit prevents the smoke from escaping. Bob posts on www.trains.com
BB


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## gunrunnerjohn (Nov 10, 2010)

A link to the post would be useful.


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## servoguy (Jul 10, 2010)

Here you go: http://cs.trains.com/TRCCS/forums/t/173684.aspx?PageIndex=1

BB


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## gunrunnerjohn (Nov 10, 2010)

Thanks, that looks like a good plan. Get your drill out Ryan.


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## erkenbrand (Dec 6, 2010)

For now I think I'll hold off on the drill. 

Everything is working well, and I picked up some pressure switches at the show this weekend. I'm going to use those to activate the second step of the auto-switch, and that will save me from cutting / isolating more rail and all of the other fun stuff. And for $5, I'm willing to do some playing.


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## overlander (Dec 24, 2010)

Being snowed in today and not wanting to clean the cruddy house , I tried this conversion on one of my switches . Just the basic conversion , mind you . I'll keep the warnings in mind though . It really works slick . I may do another tomorrow . Those would be the only two I would want that way . I was thinking about making those tracks trigger a a flasher as a reminder not to leave the power up when the train is on those tracks . I'm afraid the whole capacitor discharge system might be over my skill level . Anyway . Thanks for the How to ! Cliff


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## erkenbrand (Dec 6, 2010)

I'm happy to see it's working out for you. It's saved me from a couple of derailments now, and was worth the effort.

I'm still debating the capacitor discharge circuit. I have a lot of other layout stuff I want to get done first, and I haven't been having any problems with the switch response time. Once I get done with a bunch more layout work I'll get back to the circuit. It looks like a fun project.


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## gunrunnerjohn (Nov 10, 2010)

The cap discharge circuit is more for protecting the switches when you park on them, not necessarily response time.


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## servoguy (Jul 10, 2010)

Overlander, maker sure you don't leave the switch motor coil energized for an extended period of time or the smoke may come out. 

BB


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## overlander (Dec 24, 2010)

Yeah , I'd hate to lose my smoke alright ! But please tell me . Is there any way the smoke can escape other than leaving the train sitting still on the trigger track with the transformer power turned up ? Is that my only concern ? Cliff


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## servoguy (Jul 10, 2010)

Any time one of the coils in the switch motor is powered for an extended period of time, it may lose its smoke. This rarely happened with the coils powered from the track as the track voltage usually wasn't too high, and usually the train was running so the coils weren't powered for an extended time. 

I just made some measurements on 1121 and 1122 switches. The coil resistance of the 1121 is about 8.5 ohms. The coil resistance of the 1122 is about 9.5-10 ohms. With 12 volts on the track, when I operate the 1121 switch, the track voltage drops to 11 volts, and the current is 0.7 amps. This is almost 8 watts, and the coil is small and doesn't have a good heat sink, so I am guessing that the smoke will come out in 20 seconds or so. I didn't power the 1122 switches, but if someone wants me to, I could do it.

BTW, I have 3 1121 switches. Two of them are vintage 1948 and the other is older as it has a die cast cover on the motor. 

BB


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## gunrunnerjohn (Nov 10, 2010)

I used to have a pair of 1121 switches, but I don't anymore.  I left a 1122 (a questionable one I don't care about) powered for 1 minute, the coil didn't burn, but it got very toasty!


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## servoguy (Jul 10, 2010)

Problem is if you raise the voltage just a little, the power goes way up: Power = Voltage^2/Resistance. Do you know what the voltage was you had across the coil?

BB


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## gunrunnerjohn (Nov 10, 2010)

I used 12VAC as measured using my Fluke meter. The 12V was with the coil energized. I don't care to go crazy on the switch, no reason to burn one up for no reason.


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## servoguy (Jul 10, 2010)

The switch should operate OK on 12 volts, and most trains should run OK on 12 volts, which makes me wonder if Lionel designed the coils so that they could be energized continuously without burning up. Clearly, if you put 18 volts on the coil continuously, you would burn the coil as that would be 2.25x the power at 12 volts. I have never seen a coil burned, so that is an indication that it doesn't happen very often.
BB


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## gunrunnerjohn (Nov 10, 2010)

Yep, from the heat generated at 12V, I can imagine that 18V would be "excessive".


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## servoguy (Jul 10, 2010)

The insulation used in modern motors can stand 300 F without burning. I suspect the insulation on the E unit coil is not that good, but probably good for about 250 F which will definitely burn your finger. Trying to measure the temp with your finger is a little tricky as the coil has tape around the outside which acts as a thermal insulator, so just touching the coil isn't too accurate. I don't have a switch that I am willing to sacrifice in a destructive test.

Bob Nelson's cap discharge power supply is obviously the best solution as it will never overheat the coil.
BB


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## overlander (Dec 24, 2010)

Servo guy . If your suggesting that you may want to sell those 1121 switches , feel free to PM me about them . I'm hoping to pick up some at a train show in Kokomo this weekend . Cliff


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## servoguy (Jul 10, 2010)

You should be able to buy all you want at a train show. A box for $5-10 would be about right.


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## gunrunnerjohn (Nov 10, 2010)

All I was trying to determine was if the coil was getting hot, that was accomplished.


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## overlander (Dec 24, 2010)

I'm sure I can buy them at the show . Cheap too . But sometimes it's better to pay more to someone you know will do you right , rather than a stranger who you won't see again . But thanks for the reply and the advice . Cliff


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