# MTH RealTrax switch problem..need help????



## Lynn D Bennett (Jul 27, 2013)

I got the track all laid out and powered it up through the DCS TIU. I have not connected up the switch wiring yet. Here is the scenario:

Power on the track (train actually runs). On two switches when I manually try turn them to the opposite position the light for that new direction goes out and the switch motor makes a loud buzzing. It is impossible to change the switch manually as the motor is fighting any change. With the power off the switch moves manually (by turning the light housing). I did have to relocate the switch motors to the opposite side on one but not the other. 

Since only the bus is installed (takes power from the track) I tried jumpering the connections between the common and the opposite way the switches are set to. A very loud buzzing with a rapid oscillation of the switch movable track but the direction will not in the end change.

I assume there are contacts internally that aid in the manual turning of the switch (???). I am tempted to open up the bottom of the switch and see if I can see the problem with a look at those contacts. Is this a Pandora's box or is it pretty straight forward? I have an extra for one of the switches but not the other. I am anxious to fix this and not send the switch back to MTH and have to wait to run my trains. I suspect it would be weeks.

Anyone got insight into this. Anyone have a schematic (mechanical and electrical)?

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

The reason that happens with tubular track switches is that you don't have the proper insulating pins. Since the RealTrax system doesn't have them, something must be shorted somehow in the non-derailing function of the switch.

I'd contact MTH tech support, I don't see anything in the user's manual to suggest what this might be.


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## Lynn D Bennett (Jul 27, 2013)

*Fixed !!!!!!!*

My plan included using a completely separate power source, auxiliary power, for the switches but I had yet to install the wiring. While determining if the train was under DCS control and the track all adequately powered, I tried to manually change the switch directions to access the rest of the track. That is when I encountered my switch problem. All of the switches by default (jumper buss still installed) were connected to track power. In addition one had magnetically picked up an errant staple that was jamming the mechanism.

The solution was to remove the errant staple from the one switch and remove the buss jumper that powered the switches from the track. I made up a test wire to power each switch to test each switch. When powered by auxiliary power rather than track power each and every switch worked perfectly under test. I think using track power for the switches is seriously flawed. I don't know the mechanism involved that caused the problems I was having but using auxiliary power made it all go away.

As a point of reference I am using two MTH 100 watt power bricks. One is the fixed power source through the TIU and the other is used to power all the switches and any operating accessories I may buy in the future through the AIU. The track voltage is via the cable on the power brick and is 18VAC. The switches are using the 14VAC output on the small terminal board of the second brick.

In this problem resolution I did find a picture of the switches opened up. Boy are they involved. I opened a couple of them up to see for myself. There are two micro switches that control the power on the points based on the direction for which the switches are set. There are tiny springs and magnetic coupling to the switch motor. I can now see why these switches are so expensive.

So the bottom line is only use Auxiliary Power at no more than 14VAC for switch operation. More testing is necessary when I finally get the switches hooked up to the AIU and later to parallel manual controllers as a back up.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

The only time I fooled with MTH Realtrax switches I just plugged them in and used track power, I had no issues with that. I just don't like Realtrax in general, I never got reliable connections and it was somewhat of a PITA to work with.


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## Lynn D Bennett (Jul 27, 2013)

*Ran the train and switched the switches!*

OK..... I wired up the AIU and its 100W power brick (14VAC) to the switches and all worked perfectly (I also wired up the tracks to the TIU and its separate 100W 18VAC power brick). I ran my MTH GP30 engine over all the track forward and back. There were a few problems but nothing major. I saw a non-repeatable derailment going through the frog of one switch. The front truck was pulled off the track. I read that someone put a insulate shim on the guard rail to solve this problem on their MTH RealTrax switches. Anyone know about this? It was an old post so it many be irrelevant for today's version of the switch(??). Maybe that switch is a older version?? I need to investigate.

I have an uncoupler track on two different sidings. One was no problem and the other stopped the engine as it went through making me think something was dragging or ?????. I found the tracks of the uncoupler to be rough so I'll stone the roughness off or them and try again. I ran out of time for the testing so I'll resume the testing next week. Actually all worked well except for the few problems that just need further study.

But the point of this thread is related to using axillary power for the switch motors. That solved my problem that came from earlier testing using the track power for the switch motors.

Well...I have arrived at the end of powering up the layout and it works, mostly. I may add parallel manual switches for the track switches. I have to power up the uncoupler track but I have no idea if the DCS can control it and I can not find a definite answer in the manual. More reading is necessary, I think. At some point I'll add some operating structures and have to wire them up but that is way down the road. I need MTH Premier freight cars first.

Thanks to all that helped with my efforts.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

As far as uncoupling tracks, many of them project a bit above the track plane and cause issues. Fastrack and some tubular track ones are like that, and I suspect that could happen with Realtrax as well.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

I read on the internet somewhere that if the uncoupler track follows a curve then the center engine pickup from the twisting engine might not be aligned correctly and short the track. I am looking into that as that is my case.

I don't yet understand the black central track of the uncoupler track and its purpose. Why are their two widely space center tracks on each side of the electro-magnet? is the pickup falling in to the space between them and causing the train to stop? Why does one apparently work for a train traveling over it and the other does not. It is the curved section ahead of it? I may have to remove it from its current siding and put it in another that does not have a curve ahead of it (??).

I still have not found a definitive answer to an AIU control of the uncoupling track. I found a scanned copy of an older instruction manual in the MTH archives that may answer my concerns but it is unreadable. There is no such instructions that came with either of my two new uncoupling tracks. I will contact MTH.

LDBennett


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## Lynn D Bennett (Jul 27, 2013)

*Switch problem not solved by auxiliary power but....*

It turns out after much investigation and more switch problems, I think I figured it out. The problem is the auto-derailment safety feature of these switches. I have detailed my findings in this post below:

http://www.modeltrainforum.com/showthread.php?t=19999

The problem in brief is the switches short inner rails for the open "Y" end of the switch are not supposed to touch the ends of that adjacent tract sections. Those two rail section are really switches that the loco's wheels bridge and change the switch direction to match the oncoming train through the "y" section. When they touch it feeds back to the straight or curve input forcing the switch to hold the direction it is in. That is why they buzz when you try to move them by hand and why screwing the track down causes these switch problems.

The failure of MTH to provide a surefire way to isolate those short rail section's ends is certainly a big mistake. I have no idea how many others have been burdened by this problem. My switches were new, straight from the box. They had problems from the beginning. MTH should be ashamed to have put these on the market without guaranteed total isolation of these rail sections. The auto derailment guard feature is nice but what a shame it was not implemented correctly. I'll widen the fitment gap for those rails with a Dremel on all seven of my switches.

Now I have to figure out why one O-31 switch derails the engine as it moves on to the curve part of the switch and why one of my uncoupler tracks that follow this 0-31 switch halts the engine.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

I don't have any Realtrax here, I've always found that the Fastrack switches specifically were a lot more reliable.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

Out of curiosity do you know haw FasTrack does the auto-derailment safety feature? Is it mechanical or electrical like the MTH. I originally assumed it was a mechanical feature but looking at the wiring inside the switch tells me it is electrical on the MTH switches.

As you probably remember I investigated FasTrack for my layout and I could not get my layout in my allotted space with FasTrack so I went with MTH RealTrax. We'll have to see if that was a mistake. Fortunately, fixing this problem is only a few minute operation with a Dremel, if I understand the problem correctly.

I did get feedback on this from another forum and the poster agreed to my assumptions and my solution. I have confidence my understanding and solution are correct. I reverse engineered the switch and now understand it.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

Fastrack has a 2" insulated rail near the frog that does the switching. It's totally inside the switch outline, so there is no possibility of a track configuration causing it to fail. The manual switches are actually also non-derailing, they use the wheels to flip the track.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

AH HA: That is a better way. It allows the required isolation gap to be controlled. 

I Dremeled mine and used a jumper wire to be sure each and every one worked correctly. I also ran through them on the remote and all work properly. I hated to have to grind on the new track but the switches will never work any other way. Only some of them did not have a gap but I ran the cutoff disk into each gap to assure that there would be true isolation even with the track screwed down to the layout benchwork. All seems to be fine now and the auto-derailment safety feature works too.

Now to fix the one O-31 switch that derails the engine. I am going to machine an axle with wheels to use as a gauge so I can see what is causing the derailment. Using the engine makes it too hard to see and the derailment shorts the track...Not good. I don't have any freight cars yet so I can not use a car. If the guage doesn't give any insight I'll dig out the Xmas train cars and see if they go through the switch OK.

Thanks for your info. It was very informative.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

I'd consider filling the gaps with something like JB-Weld and smoothing to the track profile, that will keep the cut from chewing up traction tires.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

I understand what you are saying but here's another question for you.

How important are traction tires? Old Lionel trains did not have them (or did they???). My trains have to be short and light because of my limited spaces. Five to eight cars might be a limit. That is not much of a load. If I loose the traction tires will I be hurting all that much with so few cars and such a light load?

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

You probably won't have traction issues, but depending on the exact layout of the wheels, the grooves the tires sit in may cause some issues if they're not present. You don't want to "lose" them, as they sometimes peel off and jam in the rods of steamers or side frames of diesels. 

Some old Lionel trains had Magnatraction, but many had nothing as you say.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

So it sounds like I need to have some spare tires on hand. The loco came with a few but that may not be enough. Where can I get MTH tires and also who is a source for the liquid smoke. The tiny tubes that come with the engine most certainly will not be enough.

I made a wheel gauge to figure out why my one O-31 switch derails the loco. One of the short tracks of the switch sticks out far enough to force the wheel up and derail the engine. The guard rail does nothing to guide the wheels as it is way too far away from the main rail. Looks like I'll have to get out that Dremel again. I think I'll go around the whole layout and smooth up all transitions between track pieces. The track is down permanently now so smoothing transition is probably the thing to do. And yes, I know the track is tubular so too much grinding might break through the rails. I'll be careful and let moderation prevail.

I still have to figure out why one uncoupler halts the loco (??).

Again thanks for the help.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

The smoke can be had from a number of sources, I use JT's MegaSteam. For tires, I order them by the dozen from the manufacturer. Now that I'm a certified ASC, I can get them cheaper. 

I'd fix the coupler, it sounds like you have a shorted or pinched wire, that will take out the electronics if you do that too often!


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

On the un-coupler track, it is not energized as it is not connected electrically. I have only just started to investigate the problem but it appears something on the bottom of the MTH Premium GP-30 truck assembly is physically hitting the upward protrusion of the uncoupler track electro magnet (half dollar sized round item in the middle of the track section). I don't yet know what but I suspect the roller assembly pickup for the center rail. I need to pull the track section out of the layout and check it against the GP-30 with both in hand. That's for later today.

I know you and others attempted to get me to FasTack but it would not hook up my layout plan in my space. I'll have to do with what I have at this point. I'll eliminate the un-coupler tracks. I am contemplating sending MTH a long letter or EMAIL about all my problems with their products but I expect zero help.

Thanks for you help.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

I've seen issues with uncoupler tracks for a lot of track brands. Atlas, Fastrack, and even tubular track can have issues as well. The problem is that the magnet has to be as close as possible to the coupler arm, as the magnetic field degrades by the square of the distance. This forces them to try to stick it up there higher than the center rail, and that's what causes the issue.

Sad to say this is pretty much all of the uncoupling tracks, not just MTH.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

I just looked at it and the contact rollers of the engine bottom in their travel before the elctro-magnet of the uncoupling track is through pushing the roller up vertically.

The way the un-coupler is made the electro-magnet can be shimmed down to allow the roller contacts to clear. But what will that do to the ability of the uncoupler track to do its job? That is a rhetorical question as only testing will provide the answer. I think the best choice is to eliminate the uncoupler track and throw it on the pile of unused MTG RealTrax parts and pieces that I am amassing. The engine has its own uncoupler built in. That should be enough.

I will write MTH about all my troubles with their products. For the money I have invested the products should not have these problems.

Thanks,

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

Well, you could move the magnet down until you can run over the section successfully and then see how well it does the uncoupling. As you say, this will be a trial and error thing.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

I ditched the Un-Coupler track sections. I do not plan on having any operating cars so I don't need anything other than the engine's built-in un-coupling.

Here's a new "feature" of the RealTrax switches I found yesterday:

It seems that in the central part of the switch, the center rail does not supply a continuous source of power from the center rail as a train passes over it. That center rail is interrupted through part of the switch. Normal engines have spaced out multiple redundant pickups so it is not a problem. But my Lionel Tinplate reproduction of the City of Denver is unique for its passenger car lighting.

There are three rolling pedestals that support passenger car bodies strung between the pedestals and provide the lighting. Their four wheels per pedestal are closely spaced so that they do not bridge the switch center rail interruption. That makes the passenger car lighting flicker off and then on again as the train passes through the switch. I think I'll investigate connecting the wiring of the three pedestals and the observation car to allow the other pedestals to provide for the one that has temporarily lost its center rail power. I'll of course have to connectorize the connections for disassembling the train for storage. Or maybe just live with the flickering. I'll have to see if it is easy to do.

I'm sure FasTrack has its problem too but there sure seem to be quite a few with MTH RealTrax. When planning this layout I decided I did not want another track laying exercise with flex track and chose track sections like FasTrack and RealTrax for consideration. Maybe that was a mistake (??). But hindsight is 20/20. I just need to make what I have work for me, I guess. One thing for sure that I have to do is smooth all the track section's rail junctions for smoother train operation. I'll get onto that next week.

I did send a snail mail letter to MTH. Let's see if that is a better way to get a response as the email route is not working for me. It upsets me that I had to pay over $200 for RealTrax switches that I cannot use that were lost to the layout due to the MTH track planner software's inability to show accurate sizes of the switch motors. Its not the money but the principal.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

There may be a method of jumpering the MTH switch to provide constant power. Since I don't have one to look at, I'm not exactly sure what you're seeing. Any switch can have a problem with certain locomotives or cars, some are just more problematic than others.

One way I've eliminated flicker is to convert over to LED lighting and I include a large capacitor that will hold up the lights for 50-100 milli-seconds, the cars I've converted shine bright and with no flicker. 

Another method is to tie cars or the tender and locomotive for steam together and derive power from all the pickups. If you do that, I recommend a 3A PTC (programmable fuse) in the line so that derailments don't cook the wire.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

The simplest solution is to add wiring to tie the lights in each pedestal all together. One of the pedestal will then always be in contact with a part of the powered center rail. I looked and it is possible. There would have to be connectors so the train could be disassembled for storage. The problem is the pedestal is short and only has one center rail roller connection so power (for the light each carries internally) is lost in the unpowered center rail of the switch (only the O-72 switches seem to have the problem).

Another MTH RealTrax "feature" was revealed yesterday. If a loop of track without separate power is ended in the open end of two switches then only one of the outside rails is powered. Some engines (including my MTH Premier GP-30) with rubber tires might only be powered from one of the common outside rails and if that one turns out to be unpowered then the engine stops in its tracks, even if the section is fed by a MTH "Lock-on". The lock-on only feeds one of the outside rails, the one on the side onto which the lock-on is placed. I had to add a jumper on the underside of the track to connect the two outer rails together for one errant loop. This all came about when I isolated the short section of each and every switch as I noted in a previous post. The problem showed up on dead ended sidings too. But it was solved with the powered bumper, well almost.

Of the three MTH powered bumpers I have on my layout's three sidings, the internal wiring connects the two outer rails on two of the three (another quality control issue for MTH RealTrax). I added an internal jumper between the two outer rails on the errant bumper which fixed the power to both outer rails of those sidings.

It turns out you may need lock-on's everywhere on the layout and they have to be strategically placed as well. The formula of one lock-on every 25 tract section is not enough. You need them in strategic places and on the correct side of the track. MTH never tells you that!

I am pretty electrically astute with a degree in electrical engineer and over 30 years of aerospace engineering experience (been retired for 15 years). While my electrical problems eventually get revealed and I successfully solve them, what happens to the poor electrical challenged MTH O-guage model railroader? This is suppose to be a kid's toy. If the kid never does anything but a circle of track with no switches then he will be successful but add switches and he may never figure out his problems. MTH has really fallen down on RealTrax, in my opinion. I can solve my problems with it but what about everyone else?

Then there is the circuit breaker in the MTH 100 watt power brick. It is suppose to be a fast acting device. Each TIU channel also has a physical 20 Amp fuse internally. The circuit breaker appears to work SOMETIMES. If I fail to turn off all power to the tracks while putting a new engine on the tracks or the engine derails then the circuit breaker often does not pop. Instead the internal fuse blows. Everything is protected but I then have to remove the TIU after disconnecting its wiring to get at the six tiny screws on the bottom for access to the blown fuse. I have had to do this three times so far and it is getting old. At my age crawling around on the floor to remove the TIU is no easy task. I know, I have to be more careful about turning the power off at appropriate times. If it happens one more time I am going to drill an access hole in the TIU lid so the fuse for my one fixed power channel can be accessed without removal of the TIU from the layout. A removable lid over each fuse might have been a better design for MTH. I am after all using their power brick on their TIU and the their fast acting circuit breaker is not working all the time. You would think they could get it right for their products used together!

OK....Rant is over. Back to running trains! Yesterday I had two trains running at once on my layout, with sound blaring. What fun. But the array of soft key controls has me perplexed. I am going to make a cheat sheet for each engine so I can use all the engine's functionality after I determine what the three letter soft key codes mean (??).

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

Aerospace, what exactly did you do? I was also in aerospace for many years, I did fuel systems and cockpit instrumentation for military and commercial aircraft. I was the project engineer on the very first microprocessor based air data computer, that was done in the late 70's when air data was all analog stuff. 

As far as the TIU, do NOT depend on the internal fuses, normally you'll do some other damage if you get currents high enough to blow that fuse. The MTH Z1000 brick has a decent, but not super fast acting circuit breaker. The best circuit breaker I've found on any transformer has been the Lionel PowerHouse 180, it has an electronic breaker that will trip in milliseconds, as fast as it can pick the little relay! I haven't seen any other transformer that comes close.

The only time I've ever had issues with the outside rails not powering stuff on Fastrack is the small motorized units that have four wheels and a traction tire. That can happen on a switch or dirty rails, but the Fastrack standard is that both outside rails are connected together, so it's rare for that to be an issue.


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## Lynn D Bennett (Jul 27, 2013)

gunrunnerjohn:

I was a electronics design engineer for radar projects (signal processing), both airborne and ground systems. My group of engineers (I was a group project leader) did digital signal processing using discrete MSI components and micro-processors in later projects. We did signal processors for ground based radar system sold to countries around the world. One of my own earlier signal processor designs went into to space on the Pioneer Venus project as a orbital radar mapper of Venus. Another was on the F-14's on every carrier in the fleet. After 15 years of retirement I forgot more than I knew  

On the circuit breaker, is there a fast acting component circuit breaker that matches that on the Lionel PowerHouse 180, that could be added in-line. Changing out 20 amp fuses is not the way to go! I attempted to get a new Lionel PowerHouse 180 but none were available and not even Lionel could give me a schedule for their delivery. So I went with the MTH 100 watt brick that has a built in breaker but apparently it is not fast enough. If you know of one let me know. I'll try to find one myself. Have you any specs on what is fast enough. Element 14 (the old Newark Electronics) has lots of components including circuit breakers but I have no idea what is fast enough (??).

Finally, what is to the "gunrunner" part of your handle. I have a pretty good bunch of guns myself.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

Just before I retired, my last project was the X-47 UCAV fuel system, an interesting bird! 

I don't know of anything that matches the PH180 circuit breaker, one reason I like those for powering command layouts. I looked at magnetic breakers on eBay, but I didn't find a suitable one. The stand-alone magnetic ones tend to be somewhat expensive.

The "gunrunner" is because for years I've collected old pistols, mostly from the 1900-1950 era. Check my profile website if you'd like to see some of them.


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## Lynn D Bennett (Jul 27, 2013)

John:

WOW....That's some collection. I have many guns too but mostly more modern shooters and certainly not as many as you. I reload as well.

LDBennett


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## gunrunnerjohn (Nov 10, 2010)

I've probably been collecting them longer.  There are a few that are not represented there, I haven't updated that for some time.


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