Walthers switch machines


Bigboy57

Active Member
I have installed several of the switch machines and really like their ease of setup and adaptability. When using newer locomotives, they work flawlessly. My problem occurs when using my 60's versions of Rivarossi steam. I have several including the Big Boy. These locos will randomly cause the switch machines to throw. I can't get a pattern, just random, but will cause some serious derailments, especially when they throw in the middle of a passing train. Sometimes a turnout will throw on the opposite side of the layout from where the train is.

My turnouts are Atlas Mark IV and I do have the frogs juiced with the switch machines. We have tried taping magnets on the switch wires near the switch machines to act as a filter but this made no difference.

Any thoughts?
 
I have installed several of the switch machines and really like their ease of setup and adaptability. When using newer locomotives, they work flawlessly. My problem occurs when using my 60's versions of Rivarossi steam. I have several including the Big Boy. These locos will randomly cause the switch machines to throw. I can't get a pattern, just random, but will cause some serious derailments, especially when they throw in the middle of a passing train. Sometimes a turnout will throw on the opposite side of the layout from where the train is.

My turnouts are Atlas Mark IV and I do have the frogs juiced with the switch machines. We have tried taping magnets on the switch wires near the switch machines to act as a filter but this made no difference.
Do you mean the 942-101? https://www.walthers.com/walthers-control-system-switch-machine

I have to say I have no understanding of how these work, but a magnet to filter for what? If you are thinking stray RF from the old AHM motors I would think a grounded shroud of a metal can would be a better filter.
 
Do you mean the 942-101? https://www.walthers.com/walthers-control-system-switch-machine

I have to say I have no understanding of how these work, but a magnet to filter for what? If you are thinking stray RF from the old AHM motors I would think a grounded shroud of a metal can would be a better filter.
Yes, those are the switch machines. You make a good point about the grounded shroud. I hadn't thought of that. I don't have a lot of experience with rebuilding these older locos. Any tips or tricks to make it easier?
Thanks
 
Yes, those are the switch machines. You make a good point about the grounded shroud. I hadn't thought of that. I don't have a lot of experience with rebuilding these older locos. Any tips or tricks to make it easier?
I've rebuilt several of the old AHM/Rivarossi. All were hard for some reason or another. Hardest for me at the time was finding a motor that would acutally mount in the same place the old one did. Usually I had to build new motor mounts. The NWSL gear sets made for the specific models helped a lot. I also started using flexible tubing for the transmission rather than u-joints and stiff shafts. Obviously watching out for the hot frame on the loco was always and issue as I was also installing command control decoders, or PFM sound at the time.

But, I don't think I would go through the effort these days, I would go to swap meets and watch ebay for some BLI / Proto Heritage locos selling in the $150 range. That is about what one will pay for all the parts to rework one. I've picked up many that way and just let the AHM be displays.
 
Do your older locomotives have what is called pizza cutter wheel flanges which maybe too deep to navigate the turnouts?

Greg
 
Do your older locomotives have what is called pizza cutter wheel flanges which maybe too deep to navigate the turnouts?

Greg
Yes, they are the pizza cutters. For this reason I am using code 100 except for the turntable and roundhouse which are code 83. Do you think this is causing the problem?
 
Servos are picking up stray arc noise , either from the motor or electrical pickup.
Thank you for your response. How would one prevent this? Some of the locos are way worse than others. It seems the slightly older Rivarossi models (late 60s) with the motor in the cab have less issues than the early 70s models with boiler mounted motors.
 
First thing is to diagnose the problem fully . The noise may come in two forms either conducted or radiated.

To start , you need a diagram of the wiring and associated wiring ,nothing elaborate just a hand draw diagram is sufficient . We need to know how the track power is connected and how the switch machines are controlled and powered.

Also a photo of the under side of the layout wiring would be helpful.

There are things you can try but its better to diagnose the problem rather than trial and error which may only mitigate it rather than eliminate it. If you dont fully diagnose the issue , you may "mess around " until you get it to go away only to have it rear its ugly head later.

if it turns out to be conducted , the fix is probably simple and you wont have to start tearing open locomotives .
if its radiated , the solution gets more complex.
 
First thing is to diagnose the problem fully . The noise may come in two forms either conducted or radiated.

To start , you need a diagram of the wiring and associated wiring ,nothing elaborate just a hand draw diagram is sufficient . We need to know how the track power is connected and how the switch machines are controlled and powered.

Also a photo of the under side of the layout wiring would be helpful.

There are things you can try but its better to diagnose the problem rather than trial and error which may only mitigate it rather than eliminate it. If you dont fully diagnose the issue , you may "mess around " until you get it to go away only to have it rear its ugly head later.

if it turns out to be conducted , the fix is probably simple and you wont have to start tearing open locomotives .
if its radiated , the solution gets more complex.
Well, I can do that however, I have 7 60s and 70s versions of steam Rivarossi's and one new Bachmann 2-6-0. All are run on dc but as I stated before, the Rivarossi's are giving various degrees of random switch machine throws however, the Bachmann has never once caused a switch machine to throw. This tells me that there is nothing wrong with my electrical wiring.
 
Thank you for your response. How would one prevent this? Some of the locos are way worse than others. It seems the slightly older Rivarossi models (late 60s) with the motor in the cab have less issues than the early 70s models with boiler mounted motors.
hmmm, now that this is being discussed, it seams I recall capacitors across the motor power to help prevent RF interference from the brush sparks. Non-polarized capacitors in the range .22uf to 1uf were used.
 
Well, I can do that however, I have 7 60s and 70s versions of steam Rivarossi's and one new Bachmann 2-6-0. All are run on dc but as I stated before, the Rivarossi's are giving various degrees of random switch machine throws however, the Bachmann has never once caused a switch machine to throw. This tells me that there is nothing wrong with my electrical wiring.

It doesn't tell me that. When dealing with EMI / RFI just having A wired to A and B wired to B isn't enough. Theres other things that come into play.
 
hmmm, now that this is being discussed, it seams I recall capacitors across the motor power to help prevent RF interference from the brush sparks. Non-polarized capacitors in the range .22uf to 1uf were used.
Yes , you can tear into the locomotives and put capacitors across the motor leads , but it wont change the high current 3 pole motor into a low current 5 pole motor. Just putting a capacitor may or may not solve the issue , Some of the Bachmanns have EMI /RFI filters in the tender. There's whole list of variables that can have an effect. The number poles on motor , wiring , grounding , type of wire , wire routing , type of power supply , whether the supply is filtered, rpm of the motor. The list goes on.
 
Well, I can do that however, I have 7 60s and 70s versions of steam Rivarossi's and one new Bachmann 2-6-0. All are run on dc but as I stated before, the Rivarossi's are giving various degrees of random switch machine throws however, the Bachmann has never once caused a switch machine to throw. This tells me that there is nothing wrong with my electrical wiring.
Would seem to indicate that the pizza cutter wheels might be the problem??

I once had an older loco with these type wheels, and I experimented with running it with its wheels set on sandpaper (or file) ,..can't remember. But it did cut down the flange sizes on those wheels.
 
Would seem to indicate that the pizza cutter wheels might be the problem??

I once had an older loco with these type wheels, and I experimented with running it with its wheels set on sandpaper (or file) ,..can't remember. But it did cut down the flange sizes on those wheels.
Well, the pizza cutters could be causing issues but they were designed for code 100 back in the day when that was our only choice. For this reason I am using code 100 on my layout.
 
Yes , you can tear into the locomotives and put capacitors across the motor leads , but it wont change the high current 3 pole motor into a low current 5 pole motor. Just putting a capacitor may or may not solve the issue , Some of the Bachmanns have EMI /RFI filters in the tender. There's whole list of variables that can have an effect. The number poles on motor , wiring , grounding , type of wire , wire routing , type of power supply , whether the supply is filtered, rpm of the motor. The list goes on.
I am suspicious that the 3 pole Rivarossi's are the problem. I am installing a new motor in one of my 0-8-0's tomorrow and we'll see what happens.
 
Just an update. I put a new motor in one of my 0-8-0's today. This switcher is one of my most used. It was not the worst offender of the random switch machine throws but close to it. I would average 3-4 random throws per lap around the layout. I could never get a pattern or a cause and tried rerouting wires, magnets, aluminum foil tape and a few other bizarre ideas. Anyway , after the new motor install, I have had 0 random throws. This has turned into $20 well spent and will probably change motors on most of my old Rivarossi's.
 



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