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Discussion Starter #1
Are Gargraves manual switches inherently self-tending? I would need the 42" radius switches.

My track plans call for a dog bone with a reverse loop at each end. I do not need remote control to throw the switches. I just need the switch to be self-tending when the train approaches opposite the point after traversing the loop.

Are there any caveats? Would it be dependent on speed - too fast or two slow? Would small, lightweight, 4-wheel tinplate cars leading into the switch, ahead of the engine, be able to move the points w/o derailing?

I've been testing Marx O-34 switches and planned to mate them with Gargraves track. I added a rail to the curve route to avoid derailing - a common fix. But I'm having two problems: (1) Using track power to throw the switch has been problematic: not reliable and/or fast enough - even after through maintenance with Teflon dry lube; and (2) The light tinplate cars get a bumpy ride and derail often enough even with the switch in the proper position.

Any insight would be appreciated.
 

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I have about a half dozen Gargraves manual switches on my layout. They work fine and I have no issues of de-railing when backing through them. They are not as realistic as the Ross switches on my layout but I can live with that.

Bill
 

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The manual Gargraves switches come with a ground throw and are not self tending.

I think you would need to use DZ-1000 switch machines and wire them for non-derailing using a separate power supply (not track power). I have my passing sidings wired that way powered from a ZW with voltage set at around 14.5 volts. Operation is fairly reliable.
 

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They don't come "self tending" but all you have to do is add a hairspring to the points to hold then against one side. I guuss you would have to play with the spring size to find one that will hold one side tight and still let the flanges push it aside on the return trip.
Give Gargraves a call, they might have the springs in stock.

Pete
 

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Discussion Starter #6
If I understand the sum of the comments ... A train will not derail on a Gargraves switch when moving into the switch trailing the points - the wheels will move the points to the correct position. But moving into the switch facing the points can be a problem - the points not fully thrown one way or another. To solve that issue, a light spring is needed to always move the points fully into a one of the two positions.

Correct?
 

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If you approach your reverse loop with nothing to hold the switch in position, the train would derail just about every time. And if it didn’t derail going in, it might just derail going out of the loop.

If there was a spring to hold the switch in position as Pete suggested, you would be OK entering your reverse loop, but you could have problems exiting the reverse loop, especially if you don’t have a spring with just the right tension and/or if you have light weight cars. The train would travel through the loop in the same direction (either CW or CCW) every trip.

Using a DZ-1000 and wiring it for non-derailing is probably the most reliable method. The train would travel through the loop CW and then CCW on the next trip.
 

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Spring switches are actually prototypical. Tolley lines commonly used them also on coal unloading ramps.

Pete
 

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I run Lionel O-72 switches this way with no problems, I just remove the switch motors (actually, I remove all my O-72 point motors, and, just poke the points over with my finger, works for me)...........You would have to experiment with the Gargrave's ones to see if they would work reliably..........
 

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Here's a small Marx O-27 layout doing just what you want.......I disconnected the switch controll levers, and, just let the trains flip the points as they go round........Works very reliably.....

 

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Discussion Starter #11
Here's a small Marx O-27 layout doing just what you want.......I disconnected the switch controll levers, and, just let the trains flip the points as they go round........Works very reliably.....
Are those the Max O-27 or O-34 switches? I can't tell from the video.
 

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Discussion Starter #13
O-27.....
I have several of those switches. I might consider that when I get to the small radius reverse loops . But presently, I'm working on a loop with the wide radius switches. I have both the manual and electric. On the manual switch, if you remove the plastic red & green indicators, the points are easy to move. But there's a problem with the base of one point when entering the curved route. It just sticks out and the wheels bumps over it instead of moving the point (1st pic). I'm thinking of add a flexible flap to help the wheel traverse the point's base (2nd pic).

Switch.png Switch 2.png
 

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Where your arrow indicates take pliers and gently bend that flange out to meet other. I've done the same on lionel and gargraves of my own . Not a problem.
 

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Discussion Starter #15
Where your arrow indicates take pliers and gently bend that flange out to meet other. I've done the same on lionel and gargraves of my own . Not a problem.
It's plastic. I thought about a heat gun to bend it out. But once bent out, you've created a similar problem facing the point into the curve.The pivot is set back from the points base. So the base moves quite a bit when thrown. If you bend it so it's even in the straight position, it hangs out when in the curve position.
 

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It's plastic. I thought about a heat gun to bend it out. But once bent out, you've created a similar problem facing the point into the curve.The pivot is set back from the points base. So the base moves quite a bit when thrown. If you bend it so it's even in the straight position, it hangs out when in the curve position.
I wonder if maybe that points plate is worn or egg shaped at the pivot location? I'm not familiar with Marx switches but looking at some on ebay I see some misaligned like yours and some not.
 

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Discussion Starter #17
Yes. But even my powered O-34 switches have the original issue with the base point (red arrow pic). One thing I noticed on the manual switches; the problem base point is a little higher than the fixed plastic rail. The points through to the outboard user lever is a single molded piece. And that base point is forced up given the play in the mechanism . When I get my neighbor's heat gun, correcting that will be the first modification.

BTW: the pics I posted are not from my switches. But the points in the pics look exactly like mine.
 

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Discussion Starter #18
Epilogue: I'm now resigned to using accessory power to throw my Marx O-34 switches despite my attempts to have a self contained switch without external wiring. I had modified the switch rails for the isolated rail triggers and wired them internally to the coils. I'm also using a new design to prevent coil burnout. I'll post that separably.

The first switch has different coils than the second (different mfg lot/year). The DC resistance is ~ 50% higher in this switch. Thus it takes a higher track voltage to throw the switch. And that won't work except under ideal conditions of speed and train load.

The second switch had three intermittent shorts. I spent 6 hours tracking these down. Two intermittent shorts were worn enamel on coil wires touching the ground frame - worn from the movement of energizing the coil. The third intermittent short is from the previous owner cutting the diverging route using successive drill holes. That interfered with the insulation between the ground frame and the powered rail. With a high enough track voltage and a loco pulling enough cars to remain on the track, that switch will work with track power. Running just a loco or small consist doesn't have enough voltage to reliably throw the switch.
 

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Wow, lota work. Never did like using track power for switches, as you say, can be pretty troublesome.....

Separate power is the only way......
 

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Discussion Starter #20
... Separate power is the only way......
I just learned that - the hard way. Track power could work if the coils were wound for it. But then they'd draw a fair amount of power and the classic isolated rail could burn them out quickly with long trains or a parked train. It occurs to me that the mfg.'s missed the boat on early switches. Positive feedback could prevent burnout. That is, when the switch is completely thrown in a direction, it should disconnect power to that coil. I looked at adding micro-switches to do that but couldn't engineer them into the existing switches.

BTW: I did a retake on your video. I believe your using the later, plastic versions of the Marx O-27 switch. I don't have those. I have the early metal O-27 versions and the plastic O-34 versions.

On a positive note, I've read the early metal Marx O-27 switches are very smooth. And looking at them, it would seem that a train wouldn't see a difference running through the switch than on normal track. Self tending those switches is next.
 
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