Postwar O22, and Similar Tubular Switch Maintenance and Repair

Includes Prewar 711, and modern O72/O31 switches

Lionel has made 2 size of O tubular switches.    O31 and O72 curves in various designs over the years.  

Fastrack switches 031 and O72,  are not covered here.  O27 tubular switches with O27 and O42 curves are not covered here.  O27 is the nickname for the shorter tubular track made by Lionel for smaller layouts and O27 wheeled trains. 

O, O31 diameter curve switches

O, O72 diameter Curve

 Maintaining the O22 remote control switches is a simple process with many areas or steps to check.  You are fighting corrosion, wear and design changes.    The basic things you need to "fix" are cleaning dirty areas, loose track attachments, corroded or worn connections, corroded or worn contacts, some wiring, rust and replacing old lubrication in key areas.

This Classic Toy Trains O22 Switch discussion has many suggestions for fixing and maintaining these switches.   More pictures would be helpful, I have many here.

This OGR discussion also adds information.

Note these switches were made over many many years.  Some screws changed, lantern holders went from metal to plastic and more.   Make sure you don't loose the screws on a O22 switch, it may not be easy to find replacements.

Basics

There are 2 coils in the motor.  One or the other is energized to move the switch one way or the other.   Both coils have Center rail or Power available all the time.   The switch actually "grounds" the coil to cause the coil to energize.  The train wheels "ground" the non-derailing outer rail to cause the switch to activate for the non derailing feature.

When you take the cover off the motor (2 screws on the back) and remove the switch motor from the switch, (2 Screws on the back and one captive nut to not loose!), this is what you see.

This one has had an LED and resistor added to replace the light bulb.  You can clearly see the fixed voltage connection.  I would strongly suggest this be used with a constant 18-20V for these switches.  Track power may be too low at times to reliably run the switch.  The white grease in this picture shows the slide areas you need grease, but this is overdone in my opinion.

Grease goes on the lantern gear and the black base piece that slides on the bottom plate where dimpled and on either side under the light socket.  Most of the backsde of the black piece is in the air.  Grease and oil also collect dirt, use sparingly and only where needed.  The grease in this picture is a little over-done.

The copper looking Lock Hinge that "locks" the switch in place.   There is can be adjust, and is explained in the O22 modern switch below.

The other end of the switch motor.  The motor can be mounted right or left.  There are extra contacts to support the motor being mounted either way. 

There are 2 center rail contacts, but only 1 is used at a time.  The fixed voltage plug when used disables the center rail feed to the coils.  On these postwar switches, the center rail contact is wide, almost to the outer edge of the motor housing. 

2 outer rail or ground contacts,  1 used at a time. 

2 non derailing contacts that are diagonally apposed, both are used no matter the position. 

The sliding contact is 2 sets of switches. One for each coil. Grounded by the switch or the train touching the non-derailing track segment.   Once the switch is thrown, straight for example, the straight sliding switch at the end of the movement has the lock drop in place and the straight switch is no longer in contact.  This keeps the coil from being constantly active when the train is running through the switch.   When turn is thrown, at the end of the throw the lock drops in and the contacts are off the switch and the turn coil is disabled. 

The 2 control switch light bulbs are always connected to the switch and non-derailing side of the sliding switch. The light bulb draws a lower current, not enough to energize the coil.   LED lights even less.   So when the Green bulb is active in the control switch, it is telling you the turn is connected in the sliding switch and ready to throw.     Once the turn is thrown, the sliding switch dis-connects the turn side and the Green light goes out.  Now the straight side is connected and the Red light is on.  You may have the bulbs set opposite, depending on your taste.   Another reason that once thrown, the sliding contact disconnects the current flow from the coil, so only 1 light bulb is lit in the controller.

I had trouble with the switch motor shown above.     It had continuity problems in the sliding switch. This model, postwar 1950 and newer, has very little contact material under the contact ends.  These switches have the bayonet light bulbs.

Another way to tell if there are sliding switch contact problems is the bulbs in the controller.  If they are good and in the socket well, one or the other should be lit.  If one doesn't lite or is intermittent, then the sliding switch may have contact problems.

If the switch is sluggish or non-operational  90% of the time it relates to the contacts on the sliding switch.   My maintenance steps after removing the cover and the motor from the track.

  1. Clean off old contact grease on the slide switch and center rail contacts.
  2. Clean off old grease around the lantern if any.
  3. Spray contacts with good contact cleaner.  This can also be used around the lantern switch area to loosen or remove old grease.
  4. If there appears to be corrosion on the contacts, clean with a pencil eraser.  If that isn't good enough I use a Rush Eraser to clean the contact areas.  Only a little pressure is needed. It works fast.  
  5. Check all wires insulation and solder joints
  6. Check for rust.  rust in the sliding area is a problem.
  7. Test motor.  Center rail lead on the power tap post, use the ground/outer rail lead on the outer posts, one at a time.  Why not use the controller?  I want to test 1 thing at a time.   The switch needs to go all the way, with the locking hinge down.   If not, there may not be good contact along the full length of the contact pad.  Is is working and snappy?  Then leave alone.   Only bend contact arms to add pressure if needed.    How much pressure?  As little as needed.  Extreme bending may be too much and contacts may not touch correctly.  It takes experience.  Enough that the switch plate makes good contact and pushes up against the top of the 2 guide rivets, but too much adds a lot of drag.  Careful when bending the arms that you do not bend the inner arms so that they come out of the guide buttons.  The guide buttons are to keep the  switch arms aligned
  8. Once working snappy, very light coating of contact grease on the 4 switch pads, 2 center rail pads, the 2 non-derailing contact pads and the copper ground strap on the switch.  You may need to use the lantern housing to cycle the switch a few times to get a good contact path on the 4 switch points.  You should see a trail on the contacts showing good contact along the full motion of the path. If not adjust contacts as needed.  I use a tiny amount on No-Ox-Id contact grease to the contacts to help prevent corrosion over the long run.  A tiny amount is a small dab worked into a cotton swab and then lightly rub the cotton swab on the contact areas and sliding switch contact plates.
  9. Then white grease or similar applied lightly to the sliding areas on the base around the lantern area. The amount that fits on the end of a cotton swab should be enough for all the greasing.  Most of the switch rides in the air.  Note where the contact areas are under the light socket and sometimes small bumps that ride on the base plate.  The gear and sliding areas only need grease.  
  10. Test again to make sure motor is still working well and contacts don't have too much grease.
  11. Re-assemble with switch.  Test.   If needed make adjustments with the lock hinge to make sure it locks in and is close enough to the full position to prevent derailing.  See below in the modern switch section for locking hinge adjustments.

I had to bend the sliding switch contacts and add a lot of tension to get the contacts working reliably on one postwar O22.   One side was  still sluggish.  I changed out the 711-216 switch plate, with a 711-170, 1950 and earlier.  I find these easier to adjust, but both can work well.  Modern switches also use 711-170.  New 711-65 rivets are needed.  Many Lionel parts suppliers still have the rivets and parts for these switches.

711-216 slide plate from the contact side

711-170  slide plate from the contact side. Showing the taller contact material under the switch bar.  This one needed minor adjustment after cleaning up the contact areas.  Also see late prewar/early postwar motor near the end.

Check the light bulb wiring and with the bayonet bulbs, check the spring. A rusty or collapsed spring will make the bayonet bulb contact bad.   When replacing the  bulb wiring, be careful to route the wire through the hole in the bottom and out through the right in the picture below.  Then on the wire guide.   All this is there to assure it doesn't get caught in the lantern and slide mechanism.


The cast metal lantern housing on the older switch motor had been bent and it interfered with the cover when the switch was thrown.  I used needle nose pliers to hold it near the base, above the gears.  Then constant pressure for 20-30 seconds.  It bent enough to clear.   This kind of metal breaks easily if you try to bend it fast.  It may still break if you bend it slow.   Be ready to replace it if you need to bend it.  Newer models use a plastic housing that doesn't tend to bend.

Now look at the switch and the contact areas it has that connect with the switch motor contacts.  These need to be clean.  Also there is one "paper" insulator that is needed also.  This was missing on this switch.  I used card stock from a greeting card to make the insulator.  I cut T slits on both ends.  Then carefully guided the tabbed ends created by the T slits under the contact bar to hold it in place.

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Looking at the complete switch with the cover off.  Over time the connections and tabs used varied, but the basic function is the same.  The No Touch area is where the non derailing connection crosses and outside rail.   If the rail tab has bent up it may touch and needs to be bent down.  Use thick paper as an insulator if needed.   Make sure all rail tabs are tight and in place.   Soldering all the crimped connections can assure a good electrical contact.  There is also a ground/outer rail wire that connects the turn outer rail connectors.  It also connects the flat outer rail connection.  Make sure it will not short across the non-derailing lead. 

This is another version of the postwar O22 In some cases the outer rail tab that is bent over is missing and cannot touch.  This appears to be intentional.  The rail is held in 3 other places, so not a problem.  This also shows the crimp connections soldered.  I clean the area to solder, a little electrical friendly flux and a small amount of solder.   A big glob is not needed.  Just enough to assure good electrical connection. cleanup any excess flux, even the flux from the original manufacturing if evident. You can see the brown flux blobs below.


Adding insulators under and over the Non-derailing leads.    The top one is folded to protect both sides.  Some may consider this extreme, but I will never have to worry about a "short in the switch".  I find old greeting cards just right for this.


A close view of the flat outer rail.  Some say it isn't always hooked up to be functional, but all the switches I have seen have it connected to outer rail/ground.   Is it absolutely needed?  Not with inner/outer wheels both able to contact.  This would contact the flange on the wheel in the gap areas.  Probably for added common connection reliability.   For some prewar  and early post war engines with taller flanges this is where the flanges contact vs. the wheel face on the outside rail also.  Maybe this was to help those older wheels make contact.  Make sure you polish this up also.

A paper insulator was also used under the metal cover plate.   It was not always used or often left out.  It assured no shorting of the inner rail connections or non derailing connections if there were point pressure  bending the cover in. It may be wise to use a paper insulator after soldering the crimped contact areas, to assure there is no shorting.  This is the original

Home made paper insulator for a switch that didn't have any.  Old Greeting cards used.

I switched out the bulbs in the switch motor and control switch for an LED bulbs.  All three incandescent bulbs were 18v .1 Amp.  5.4 Watts for all 3.   Traditional incandescent bulbs soon add up to a lot of power.  LED light bulbs prevent melting the lantern covers.   Also the old style switches with the bulb exposed do get hot.   

The bayonet style bulbs work the best for remaining tight in the socket.  The screw in bulbs may come loose over time. 

I modify the fixed voltage plug for better contact and reliability. I cut the shoulder off so it would push in all the way.   With the shoulder it only went on the pin 1/3 of the way and didn't feel secure.   Taking off the cover and pushing it on all the way, the cover would not go back on with the shoulder there, almost but not enough.    Then I cut a small groove with a file where the spring contact arm is.   Now when inserted the spring acts as a catch.  Now it should not work off the pin as the train goes by time after time.  Careful, cut the groove too deep and you will get to the metal and then your track will have constant high voltage!    A little No-Ox-Id on the pin helps the contact also.

Modern O72 switches

I checked a new in the box 6-65165/65166 O72 right and left hand switches. These are labeled made in China.  Also O31 curve  6-5132 and 6-5133 switches. Point of manufacture not labeled, but maybe USA since the Lionel, Mount Clemens Michigan name is embossed in the switch, 22+ years old?  While the O72 just have Lionel LLC.    The O72 switches both switched well out of the box.  The O22 did not.  Both were shelf queens, but unused and unopened.

For the O72 switch all the connection joints are now soldered or are wires that are soldered.   For the O72 were there are plates in the O22 switches for the outer rail and center rail connections, there are just wires.  This follows the traditional prewar 072 switches.

The modern  O22 is similar to the postwar switch layout with metal runners with crimped ends.   Where the top non-derailing lead crosses the outer rail tabs, there is only 1 tab, not 2 as discussed above.  No chance of shorting there.  .  The other places where they cross over rail tabs, they have insulating pads. These modern switches still have the flat outside rail contact electrically active.  Only a tall flange will touch it.  

I cleaned, fluxed and soldered each crimp area.  Just a little bit of solder to get a connection.  Not a large blob.  These modern switches are thermoplastic and too much solder heat is a problem.  Then I washed the excess flux off.


The O72 sliding switch has the taller contacts and liberal contact grease on the 4 pads.  The motor side non-derailing contacts are a circuit board that cannot be bent up.  But the contacts on the track side are spring loaded.  I added No-Ox-ID to the main ground strap and the 2 non-derailing contacts.   Much lighter than the amount Lionel used.  Too much can interfere eventually.

The one thing I had to do was bend the center rail spring contact so it was centered in the contact area on the motor.   It was at an angle and on the edge of the contact strip.  I didn't want it loosing contact in use.  Just check and make sure it is on the contact pad well. The center rail contact pad is not as wide as the O22. 

The O22 sliding switch had the tall standoffs, but no contact grease.   Also it was the postwar style were you bend up the 2 edges to increase contact pressure for the non-derailing contacts if needed.   There was light corrosion on the switch contacts. The backing metal for the switch felt to me like a lighter gage or not as well tempered metal.  It works.    There is also no grease on the gear or  sliding area of the switch around the lantern area.


I used a pencil eraser to clean the pads of corrosion.  It worked, but sluggish.  I added a  double, step bend at the ends of the contacts to add pressure and keep the contacts flat.   A light coating of No-Ox-Id contact grease and the switch motor was working well.

Concern on mechanical design and quality   The O72  Right hand switch when set to straight, held nicely, but in the turn position it can easily gap enough to derail.   The slot for the driving pin has a lot of excess play.  I measure the pins and the slots of the 2 switches.  I also measured a postwar 022.

What tolerance was allowed?  I don't know.

O72 Good on the left vs. Bad slot on the right. Good is oval,   Bad one is not oval.

 

 It looks like the right hand switch has a manufacturing defect, the slot was cut too wide.  Quality isn't getting it past the inspector, it is making it as designed!   I made a shim to tighten up the slot .030"/1.5mm on the bad turn position side of the slot.   If I had bought these new, it would go back for replacement.  They have been on a shelf for a few years.

This is a pair of my 3D printed L shaped shims with skirts.   They are so small, without the skirts they would not stick and would fail.  Skirt is cut off later.  They worked with a .4 nozzle, but a .2 would be better.  Shim is super-glued on.


Locking Hinge Adjustment,  this is where we can adjust out some of the slop from manufacturing tolerances

There is a joggle in the locking hinge when looking at some of the switch motors.  One side contacts the locking hinge for the turn position, the other side contacts the lock hinge in the straight position. This means by careful bending of the locking hinge one side or the other, you can adjust the "slop" in the turnout in the locked position.   There was a design change in the early prewar switches to enable this adjustment.

Adjusting the locking hinge as needed takes some practice.  This is the O22 with the noticeable joggle.  In this position the bottom tab is contacting the hinge, but the top is not.  Once thrown to the other position the top will contact the hinge, but the bottom will not.  It works to keep the switched track against the rails both ways.  This Locking Hinge adjustment should be done with the switch attached to the motor.

Light Bulbs

The O22 screw in light bulb is the traditional design.  One was just sitting in the housing.  It had not been screwed in.   In other O22 modern switches with the screw in bulb, I found the factory had used a glue on the top of the bulb threads to keep the bulb from loosening.  I had to use needle nose pliers on the metal base that was exposed to get it out.  The remnants of the glue were noticeable on the top thread. 

The Modern power tap post is now a split post.  Pushing the Fixed Voltage plug on the post for the O22 was a press fit.  A little contact grease was needed. If the split post is bent in, together, it may be too loose.  The split allows you to use a small straight blade screw drive to adjust the diameter bigger if needed.  Careful, they don't survive many adjustments.

Warning about the light bulb in the O72 switch  This switch does not have the standard "bottom" in the light bulb base.  Usually with bayonet bulbs there is a non powered spring with the power contact and insulator on top of the spring.  For the O22 there was a 2nd insulator under the power contact in the bulb base.  The power wire going through the spring.  On this design no bottom insulator.  The spring is powered and relatively large and no insulator protecting it.   DO NOT CHANGE BULBS WITH POWER ON.   Reports are the bulb power spring easily causes a short. The wiring is thin and it caused the power wire to melt off the insulation or break.   In this case wire was not heavy enough to draw enough current to cause the transformer circuit breaker to trip.  The switch motor had to have wires replaced to work again. 

Wiring, Materials and Final notes

Some have voiced concerns about the gauge of the wires in the new switches.  The O72 and O22 are similar gauge wires.  I am not about to destructively test a postwar and modern switch motor to see if they can survive a direct short before a ZW 275 breaker trips.   If you want, a fixed voltage plug with an inline fuse may be the best to protect the switch.  How big a fuse?  Incandescent vs LED bulbs and the switch power.   1-2 amps? ToBeTested.

The older switches were bakelite. A thermosetting plastic.  Stable material with good wear and resistant to heat and solvents.  Heat from soldering usually had little effect.

These new ones are thermoplastic and soldering heat can melt them.   Be careful with heat and any track cleaning fluids.  Bright sun or heat may warp them.  Since the wear properties are not as good, I believe this is the reason a metal slide plate under the one end of the switch was added to the modern O72 switch, but not the O22.  Both old and new have the sliding tabs under the switch, with bakelite an extra sliding surface was not needed.

It seems to me the postwar switch has a little more of a chisel point on the ends of the switching track where the train enters the switch.  That may be from wear.  A little careful filing can add it to the modern switches if needed.   This may help with steam engines front trucks that don't have enough pressure.  They tend to rise up when the flange is dead against the rail and catches in the switch if there is any gap.   When riding normally, the wheel is centered and the flange is not a problem.

Vertical slop at the pivot area of the frog seems to be to be .010-.020" more than the postwar O22.  Is it a problem, I don't have enough experience with the switch to know.  Might be something to check if heavy engines have trouble.

The O72 backing plate did not have the hole to match the hole in the switch on the end.  Traditionally a screw down hole.  The one between the straight and curved end of the switch.  Neither is the hole re-enforced to take a screw to hold it down.  It would tend to crack if a hold down screw was used.    May want to tape over the hole to keep dirt and insects out.  All 3 Screw down holes on the O22 were re-enforced and had a hole through the backing plate.

Are the metal rails the same specification steel as the postwar switches?  That would take a lab to determine.

Conclusions

What are the options for using the modern switches?  Design looks good, but check for manufacturing defects and proper adjustments. It is the quality of the product that matters.  Then test for reliability.  Same thing with an Prewar, used, O22 switches since you don't know how they were used, stored etc.

As long as the sliding switch is adjusted well and has good contacts, either motor should work.  Adjusting the locking hinge for a specific switch may be needed. 

Time will tell if the modern switches will be as durable as the well used postwar switches.

Non-Derailing rail is not consistent

The  Non-derailing rail on the turn side of the O72 is the opposite outside rail compared to the O22.  It works, just be careful during assembly.

Name plates

The name plates for the Prewar 711 are held on with bent tabs, Postwar O22 are riveted on,  Modern O22 screwed on and on the O72 switches, glued on.

Coils

To test the coils, ground then directly at the solder connection to the coil.  If they are still sluggish with no mechanical drag causing the sluggish response, the coils may have been overheated and may need to be replaced. 

Results for 031 curve switches.

Using these tips I have turned a non-functional postwar O22 switch and even non functioning modern switches into reliable switches.

Controllers

The controller is a momentary contact, grounding switch.  It grounds the Outer posts on the switch to the common or outer rail connections.   The middle wire from the control goes to the center post on the switch or any ground/outer rail connection.  This may allow you to use 2 wires to the switch and a 3rd to a common ground on your layout.  Simplifying the wiring.   This switch can be duplicated with modern components.

The picture below shows an early model switch with the cover removed.  2 screws in the bottom of the controller allow you to remove the top. 

Often the wires need to be replaced after 30 or more years.  The wires in the picture have hard, cracked insulation and need to be replaced.   If you use the 3 wire cable as a replacement, the middle wire in the cable goes to the ground or outer rail connection. 

The light bulbs are connected in parallel with the switch.   Any time the slider switch in the track switch is connecting one side of the switch, the light bulb will have power.  It is grounding the coil in the switch, but the light bulb doesn't pull enough current to throw the switch or cause too much heat in the coil.   When replacing the bulbs, make sure they do not draw more current than the original 18v rated bulbs.  Using modern LED bulbs will reduce the power draw for the lights and through the coil. 

There are 2 major variants.  This one shows the colored bulbs with no cover.  Newer ones use smaller, clear bulbs with colored lenses in the control.    I recommend LED bulbs on the older ones to assure little fingers don't get burned by the bulbs.

Common problems with this switch is a broken return spring or a broken contact.    Make sure the contacts are clean and don't have a corrosion layer.   When using the switch, teach young users to move the switch just enough to work.  Continually moving to the "stops" puts stress and wear on the springs and the contacts. 

The backside of the switch.  The metal plate is the common ground or outer rail connection.  The light bulbs and switch are connected to this plate.

By changing the outside wires at the switch you can change how the controller switches to turn vs. straight.   The lantern cover can be installed in 90 degree increments so you can set red/green to show as you desire.   Often Green for straight and red for turn.

Prewar 711 O72 switches, early version.  

Prewar 731 switches are similar to the later 711 switches. They use the T rail track, not the tubular rail. 

The prewar 711 O72 switches have the following differences compared to the postwar O22, or modern O72.  They are 82+ years old and need more help.

The following pictures show what to look for in 82+ year old switches.

First look for Zinc pest, is the metal sound.

The rails may be knocked out of position and bent.  You may need to fix bends, rail ends, rail position and corrosion problems to make them useful.  Make sure the non-derailing crossover is tight at the rivets.


The rails that activate the non-derailing feature are insulated and closer to the switch.  In this case another rail has been knocked out of position.  This is an insulated rail.  Be careful you don't knock the insulation out of the rail when you move it back.

The rail pins are in the ends of the rails to help shorten the center rail gap when going through the switch.  The non-derailing rails are NOT connected to the outside rails.  The center pickups will roll over these rails.  On later 711 and postwar switches these rails are plastic/bakelight and not electrically active.

 This shows the other end of the 2 rails that have been knocked out of alignment.  This switch uses standard rail ties to hold the ends of the 2 track sections.

If you want to rewire the switch to make 2 "inner" outside rails activate the non-derailing feature similar to the modern O72, you will need to find a way to undo the rails on the frame and insulate them.  Insulating them at the crossover is much easier.  On the metal housing, bending the tabs may not be viable.  If you do this non-derailing modification, do NOT keep the existing non-derailing rails connected to anything.   Disconnect them to prevent a center pickup to outside rail short. 

The other side of the switch, where the motor mounts.  There is a hollow section in the casting that is filled with an insulated insert.  Similar to postwar and modern.

More of the backside wiring.  In this case the center rail continuity wires were all gone and had to be replaced. 

The prewar motor is similar to the postwar for the sliding switch, but the locking mechanism is a different.  In this case, the board was broken.

In this example, the board is intact, but there is not a good way to adjust for both locking directions independently.  

 

Later Prewar, very early postwar switch machine. 

I found this variant of the slider switch in one postwar switch motor.  My estimate is this is a very early model of the postwar O22 motor.  It looks like this is a carry over from the prewar, 711 later model switch motor.   For the Prewar 711,  the 1 mounting holes were bigger.  It has a voltage tap added.  The switch contacts were originally designed to stand taller for this design, they went through the sliding switch board that had 4 ears.   There is one problem with this design.  The Locking Hinge will only adjust the centering of switch.  It touches the rivet head in the middle,  the same area of the hinge for either position. It will not allow adjusting both positions as the later design with 2 contact points on either end.    The only way to adjust this switch is to adjust for 1 side by bending the bar and then use solder, or something similar, added to the other side of the lock hinge bar to get the adjustment needed. 

This motor also had the end of the shaft sealed, probably to keep dirt out, but may have caused air resistance on one direction.

 

711 considerations

The insulated rails need to be checked to assure they are not shorting.  What do you do if you have to replace the insulation paper and don't want to bend the tabs?  Remove the paper, usually bit by bit.  Then use pieces of toothpicks to hold the track centered in the tabs and off the plate.  Then use liquid tape type of products.  Brush on as liquid and let harden to hold and insulate the rail. 

After cleaning the corrosion on the contact areas of the rails, re-forming the rail ends, re-soldering and replacing some of the missing wiring in these prewar switches they can be usable.  Over time some of the rails have been dinged and bent.  It is not easy to remove dings in the top of the rails.

The outside straight rail that runs the length of the switch on both prewar switches will move within the locking tabs with a little tapping,  Not good, you want them to stay aligned correctly.  As shown in the picture above, some of the other rails slid in their mounts.   Tightening the cast tabs that hold the rail doesn't work well.   The postwar and modern switches have a different and probably better design for retaining the rails.  Impossible for them to slide out of position.  

Going fast through the switches could be a problem when relying on the non-derailing feature on the early prewar 711.  The early prewar 711/O72 switch has about 1/2 the distance for triggering the non-derailing feature compared to the later prewar 711, postwar O22 or modern 072.  This is why you need a postwar motor with the voltage tap run at 18v, to assure a speedy switch action.  It will not be easy to insulate the end rails where they are held in the metal base if you want them to become the non-derailing switch similar to the Late Prewar 711 or modern O72.

Summary

I do not recommend using the early prewar switch motors.  Part availability, no dual side adjustment and lack of a voltage taps are the main problems.  I would suggest using a Postwar motor on these prewar 711 switches.  You will have to drill out the 2 screw holes on the postwar switch motor to work with the larger mounting screws for the prewar 711 switches.

The prewar 711 switches survived  and can still be made usable.   That is amazing.   I do not see them as the "best" switch design.  Later on Lionel changed some of the design elements for good reasons.   If you like them or want an all prewar track, good.  I am going to use these reconditioned switches, but I do not see them as my first pick for an O72 switch in the future. 

As I find out more I will update. 

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Last update Oct 11, 2022