Lionel 0-27 Switch Question

[Anonymous]

I run about 10 Lionel O-27 1122 swtiches on my layout. When I 'park' a train in neutral on a switch, the switch makes a 'buzzing' noise.

Is there something wrong with my switches or do 'they all do that'.

Would modifying the switches to run from a fixed voltage supply (not track power) eliminate the buzzing ?

Thanks in advance,
Jeff

[Big_Boy_4005]

Don't do that for too long. The nonderailing feature is active, and can burn out the switch motor if left on too long.

027 switches can't be modified to stop that, because of the way they're made.

[Anonymous]

Big Boy,

Would you please explain how the derailing feature works.

(I know what it does, I don't know how it does it)

Thanks,
Jeff

[lionelsoni]

Actually, they can; but it's more complicated than simply running them on a fixed voltage. The first step is indeed to disconnect the coils from the center rail and bring that connection out. But then you have to power them not from a fixed AC voltage but from a capacitor (connected between the running rails and the common connection between the coils) fed through a resistor from a DC supply. Very little current is needed; so the DC supply (for all your switches) can be just a diode from an AC accessory voltage.

I use a 4700-microfarad capacitor and a 10-watt 100-ohm resistor. A 1N4001 rectifier diode will do nicely for the DC supply. Be sure that the polarity of the capacitor and the diode are matched. That is, if you connect the negative side of the capacitor (perhaps marked with a stripe) to the running rails, the cathode of the diode (also marked with a stripe) should connect to the resistor(s).

Here's how it works: The capacitor, like a battery, supplies enough energy to throw the switch; but, after it is discharged in a fraction of a second, the resistor cannot supply enough current to damage the coil. After the train moves off the switch, the resistor can recharge the capacitor in a few seconds.

[Big_Boy_4005]

Well Jeff, the non derailing feature simply uses the wheels of the train to bridge between the main outside rail, and an insulated section of rail, usually the short rail segment coming away from the frog. There are variations on where the insulated segment is located, since there have been design changes over the years, but the principle remains the same.

By parking the train over the switch, you are energizing the coil as if you held the lever on the controller for a long time. In either case it is not good for the life of the coil, since they tend to heat up, and can even melt the surrounding plastic rendering the switch useless.

Bob is correct in saying that modification is possible. However, it sounds like a more difficult project than you may want try, and keep in mind HE IS AN ELECTRICAL ENGINEER. (I read his profile)

One final thought here, and that is that in O gauge switches like the 022 this problem can be avoided as long as the fixed voltage is used. Those motors have a set of contacts that move once the switch is thrown, thus deactivating the track's nonderailing connection.

[Anonymous]

Thanks Big Boy. Now I get it.

[lionelsoni]

Well, Elliot has outed me. But this is not rocket science, Jeff. If you want to try and can solder a wire, I think I can talk you through it.

[waltrapp]

Actually you can rewire the coils to run off of fixed voltage. It's not too hard and is described on Lionel's web site.

However, this does NOT solve the problem of parking a train on the switch and having the coil buzz non-stop. If you rewire using Lionel's directions the power to switch the switch (to power the coil) comes from fixed voltage but that doesn't stop the switch from trying non-stop if an engine is parked on the switch.

Bob's complete rewiring is the only way. The 'better' switches do have devices (wiring) in them so that they 'know' that the switch was switched and won't keep trying.

Bob, I think I'm going to print your description and mull it over and decide if a klutz like me can pull it off. I have over 30 Lionel O27 switches and am starting the process of replacing them with K-line's O27 switches. If I can kill the buzzing I might now replace all of them

good luck - walt

[waltrapp]

Bob,

I printed your comments and showed it to a co-worker that has an electrical background. He felt that he would need either 1) more detailed information, or 2) preferably a schematic.

Any chance of you supplying 1 or both??? My friend's not a train guy but even after I explained O27 switches to him he still felt that he needed more specific information.

I have not yet re-wired any of my 36 switches to use fixed voltage, but if I can pull off your 'buzz fix' then I will be visiting Radio Shack alot over the next 10 months! I have a token O27 27" switch asking to be experimented with!

thanks - walt

[lionelsoni]

Let me try to describe the circuit in more detail--it's not that complicated:

First, identify the common connection that both coils have to the center rail. This should be obvious because one wire from each of the two coils is connected to it. Cut them loose from that connection, connect them together and to a new wire, to bring that node of the circuit out from under the switch-motor housing. The coil wires are enameled magnet wire; so you have to carefully remove (scrape) the enamel from the ends before soldering.

Get a 4700 microfarad electrolytic capacitor with at least a 25-volt rating. Radio Shack has them rated at 35 volts, which gives a nice safety margin. Connect the common coil wire that you brought out to the positive terminal of the capacitor. Connect the negative terminal of the capacitor to the outside rails. The negative terminal is probably the only one marked, with a minus sign. You can solder directly to the track or use a lock-on or use the terminal on the switch that is attached to a shiny metal plate. If you solder to the track, be sure not to use the non-derailing rail sections on the switch. The capacitor is now connected to be a power supply for throwing the switch, if it were charged.

Get a 10-watt 100-ohm resistor. Radio Shack sells one. Connect one end of this charging resistor to the positive terminal of the capacitor. The other end will be connected to a positive charging supply.

Get a small rectifier diode. Radio Shack sells 1N4001's, with a 50-volt rating, which is plenty. For the charging supply, use an accessory transformer voltage. If your transformer is properly hooked up, one side of the accessory voltage is already connected to the outside rails; so the accessory terminal is providing a constant AC voltage relative to those rails. Convert this to DC by connecting the anode of the rectifier diode to the accessory voltage. The cathode of the diode is then the positive DC supply to which you can connect the charging resistor for all of your switches. The cathode is at the end with a stripe around it. The fact that this DC supply is unfiltered and pulsing 60 times a second is unimportant. It will charge the capacitor every bit as well as any more complicated supply.

I normally put the capacitors and resistors under the table, as close under each switch as is convenient, and run the charging supply wire from switch to switch and back to the transformer, where the rectifier diode is located. If you already have the AC accessory voltage distributed around your layout for other purposes, you could keep things simple by using multiple rectifier diodes located close to the switches and each tapping individually into the existing accessory power. They don't cost that much.

Let me know if any of this is unclear or if you need any more explanation.

Good luck!

[waltrapp]

I exposed the coils on one of my switches and had only 1/8" to 3/16" of wire available to work with. I tried pulling some 'extra' from underneath but none would come. There was no slack to be had.

I should have posted my question here on the forum but contacted Bob instead via e-mail. Bob asked that I put the question here - fair request - so that ALL would benefit. It seemed such a crazy idea that I didn't want to embarrass myself in front of this whole group, but here goes:

Since I couldn't get enough wire to work with (and I had 2 others look at this with me) I came up with a crazy alternative. let me preclude this by saying that I understood clearly what Bob was saying to do, even though I had no understanding of the theory behind it. My crazy idea was this: COMPLETELY isolate the switch from the rest of the layout using dummy pins in the center rail on the divergent path, the straight path, and the "lead-in entry way" path. OK, I understand that this means there's no power at all going to the rails to run a train thru it so I thought I'd put a 1/2 piece of track on the "lead-in" path and move the dummy pin to the end of that 1/2 track. I would then put a lockon on that 1/2 piece of track and connect wires to it for power.

I was then snip the HOT wire leading to the lockon and apply all of the electrical connections there. In effect the middle rail of the switch (and 1/2 track) were an extension of the coil wire that I was supposed to snip. I figured that if I could get enough power to the switch rails to let the engine run thru then that's all that mattered.

But not understanding what the total effect of all of the electronics was, I didn't know if this was crazy or not. Bob was kind enough to answer me and here's his response:

Walt,
I don't think that would work. You would be powering the center rail of the switch with the DC voltage on the capacitor. The instant that the pickup roller went onto the switch, it would discharge the capacitor into the transformer winding that is powering the rest of the track. Then, when the locomotive pickups were fully on the switch, the train would stop.
I think that you will have to get to the windings somehow. There is nothing wrong with unwinding a turn or two from the solenoids to get the elbow room that you need to make the connection. This will have no measurable effect on their operation.
I would not use tape to insulate the connection. If you can get hold of some heat-shrink tubing, that would be much easier to put on and less likely to come loose with time, the way tape will. Use the smallest diameter of tubing that you can fit over the connection and shrink it by holding a soldering iron close to it. The soldered connection is easier to insulate if all three wire ends point the same way. Then, after you solder the wires, you can just slip the tubing over the joint without having to thread the wire through it.
Be sure to get the ends of the solenoid wires scraped clean before trying to solder them. Oftentimes they are lacquered with a transparent or yellow-colored lacquer that makes them look like bare wire, even though they are surely insulated.
Would you mind posting your question, along with this reply, on the forum, in case anyone else is trying to try this same trick?

Bob

[waltrapp]

I got to the wire another way.

I turned the switch over and cut a 'flap' in the base directly under that wire by the coils that I was supposed to snip. Using a cutoff wheel in a Dremmel, I cut a 1" wide by 1 1/2" or 2" long flap, bent it back, and exposed the wire. I snipped it down there. I turned the switch back over and pulled the wire thru the opening. This gave me about 1" to work with.

As a little experiment, I also cut the red tape that was holding the wire to the coil because I could see the wire traversing the width of the tape. This freed up another 1/2" or so.

I then used an Exacto and carefully cut a slit in the insulation about 3/4" long, leaving insulation on the wire nearer the coil (since these wires cannot touch the base that the coils sit in).

As Bob said, these wires are supposed to have some sort of coating on them that needs scraped off. I couldn't see anything that or feel anything that resembled a coating. I took the Exacto and very delicately tried to scrape them anyways. Since I couldn't see or feel any difference I can't tell if I got it off or not. I've never worked with wires as thin as these and was a bit intimidated about breaking them.

After performing this surgery, I will change the way I expose the wire on the bottom of the switch. I landed up cutting thru the ground wire because I didn't know it was there. It would be easy to do even knowing it's there! What I'm going to do on the next one is measure in about 1 1/2" to 2" from the edge directly below the wire. Then I will make a 1" cut parallel to the side, meaning it's also perpendicular to the wire that i want to snip. I will let the cutoff wheel drop down and 'snip' the wire. This way I won't have to cut an entire 'flap' into the bottom and risk cutting thru that ground wire.

Not only that, but the flap is almost impossible to bend back and get flat. I will probably have to cut the flap off to get the switch to sit flat on the layout. My alternative method completely eliminates this worry.

BTW: I opened up 3 or 4 switches and I know that there are at least 3 different wiring patterms. They are all BASICALLY the same but some have the wires more exposed and are easier to get to than others.

I have not yet bought the electronic parts and performed Bob's fix. I'll be back after I do!![:)]

- Walt

[lionelsoni]

The way that I get inside a switch is by drilling out the rivets that hold the plastic and steel sandwich together. Replacing them with screws as necessary is obvious, except for the frog casting, which is peened on the bottom to act as a large rivet. I drill the casting all the way through down the center of the post and tap it for an 8-32 (if I remember correctly) flathead screw short enough not to protrude from the top.

[waltrapp]

Bob,

I thought about drilling out the rivets but I've read in many places that it's virtually impossible to reassemble the thing. I've never tried first hand, just repeating what I've read numerous times. You, AGAIN!, are the first person that I've heard of that had successfully drilled out and reassembled the thing.

I do think my alternate solution for freeing up some more of that wire will work. If not then I'll take the switch I've been experimenting with and use it as my guinea pig to see if I can do it.

thanks - walt

[waltrapp]

just came back from Radio Shack - empty handed.

I have to give the cost of doing this upgrade a bit more thought to see if I really want to perform the surgery or sell them (they seem to be going for $15 per on eBay) and replace them with K-Line's (I already bought 4 of the K-line switches and like them). K-line's cost $25 per and if I can get $12 to $15 per for my Lionel ones, that's only a $10 differential. OK, now factor that into the prices I got at RS this morning:

Diode (99 cents)
Resister ($4)
Capacitor ($5)
TAX (70cents)

To be fair about it the Diodes and Resisters come in a 2-pack. But the capacitor is a singleton. $11 to see if I WANT to do this repair. Or as the store guy said, "look at this way: buy another capacitor and for $17 you can do 2 switches". that's still $8.50 per switch. Considering I have 30 27" ones and 6 42" ones, OUCH!

I'm leaning towards maybe doing the six 42" ones and replacing the 27" ones.

Oh well, I thought I'd report the news.

- walt

[waltrapp]

Bob,

Am I correct in assuming that EACH switch requires its own resistor/capacitor combo?

thanks - walt

[Big_Boy_4005]

Walt, Radio Shack pricing is INSANE!!! If you have an electronic surplus store near you check there, or try All Electronics or Digi-Key online. I'll bet you can pick up all the parts for all of your switches for that price.

[spankybird]

I only paid $25.00 for New K-line low profile switches delievered. Maybe you should relook at replacing the Lionel with new K-line.

[lionelsoni]

Walt, generally, yes. However, if you have pairs of switches that normally work together, like a crossover, you can power them from the same resistor-capacitor network (and control them from a single controller). You can certainly save a resistor that way. There is a chance that you may have to double up on the capacitor anyway if the switches don't throw easily; but I would bet that one capacitor would be enough.

I have the advantage of a sack full of suitable capacitors that I salvaged some 30 years ago from a line printer at the company I worked for then. It's true that Radio Shack is pricey--but handy.

[waltrapp]

spankybird: As I mentioned earlier, I have already replaced 4 Lionel's with K-line's low-profile (as completing 'surgery' on each K-line they are great now). That's why I'm not real crazy about spending $8 per Lionel switch. However, maybe I'll do it for the 6 42" ones I have since I do plan on keeping those.

Bob, I was surprised how big the resistor and capacitor are. Is there any problem with placing all of the electronical components near the transformer rather than near the switch itself? That is, is proximity important or is just having the components in-line "somewhere" all that matters?

[lionelsoni]

As I said earlier, I normally put the capacitor and resistor under the table. But I doubt that you would have any trouble locating them remotely, although I've never done it that way.

Just to be sure you've got the right stuff, the capacitor should be something like 1 inch in diameter and 2 inches long and the resistor about 3/8-inch square by 2 inches long.

[waltrapp]

Bob,

Thanks for confirming, both the location and the "size" of components. Yes, the RS guy showed me parts that match your description.

- walt

[Anonymous]

So, you guys got me all excited to convert my 0-27 switches to fixed voltage. I have a range of Lionel switches from all different decades. The first three went smooth, but on the fourth I broke the coil winding wires.

Unfortunatly it's the inside wire that broke (that closest to the spindle). I was thinking I'd just unwind the wire off the spindle (isn't that what cordless drills are for, then re-wrap it after getting the other end of the wire exposed a little more.

Has anyone ever tried to re-wind one of these?

I guess I should learn that if it ain't broke don't fix it.

[:)]

[lionelsoni]

I've done it (successfully) with an e-unit, but not with a switch. They're very similar coils. You might as well try it, since the coil is useless unless you rewind it.

Those coils are what is called "jumble-wound", which means that they didn't try to lay the wire turns neatly side by side. So you can jumble-wind it back on yourself without worrying too much about overfilling the spool. Just don't zig-zag quickly back and forth, but slowly scan from one end of the spool to the other.

[waltrapp]

Bob,

One last (maybe [:)] ) question: Can 1 diode handle multiple resistor/capacitor setups. I'm thinking 'yes' since the diode only has to handle 1 switch at a time, right? After I replace my 27" switches with K-line's, I still will have six 42" ones that I plan on keeping. Can one diode handle six hookups?

I know it's the cheapest of the components, but it's a matter of trying to limit hardware and wiring on my Christmas FLOOR layout (14'x14'). But I always error on the safe side, so if there's ANY issue at all with using just one diode I'll use 1 per 'x' - if you can help me determine the value of 'x'!!!!

thanks again - walt

[lionelsoni]

One diode should be able to handle six without any trouble. The only reason to use a big diode would be to improve your chances of its surviving an accidental short circuit.

[Anonymous]

test

[waltrapp]

Well, I finally broke down and bought enough of the components from Radio Shack to do 6 switches. I took the one that I already had opened (mentioned earlier in this thread) and hooked it up as Bob Nelson explained (Bob - thanks for the schematic, I couldn't have done without it).

It works great!!!!!! No buzzing, not even with a car parked on the non de-railer part of the switch for one full minute!!!!

I have replaced a dozen of the Lionel 27" ones with K-Line's. I now will keep my six Lionel 42" switches and use this electronic solution on them. I'll give my nephew my 30 Lionel 27" ones. Poor kid! [:)]

thanks for all the advice. This might be one of the all-time record holders for threads taking a break in between posts! [:)]

- walt

[GPJ68]

Thanks Walt for following thru on this, and Bob for the detailed how-to. I've been pondering this for awhile myself, but hadn't seen the beginnings of this thread. Answered alot of questions (and raised one or two more....).

[lionelsoni]

Walt, I'm very glad it worked for you. Thanks for posting your results.