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Discussion Starter · #1 ·
I have an old Hornby R376 LMS Class 4P Loco (4-4-0) which is a pretty good runner, especially after I converted it to DCC and reused the smoke pickups as additional power pickups. It will crawl slowly around everywhere on my layout except over my Peco curved insulfrog points. Half the time the middle tender wheel will short across the frog (to the other rail just outside the main rails) which of course stops it dead.

Any ideas how to fix it? I thought of some ideas but I don't really like any of them.

1) Somehow insulate the middle tender wheels with rubber tyres. I don't think they are pickups anyway.
2) Do something to make the middle tender wheels less floppy, they seem really loose.
3) Treat the isulfrogs as electrofrogs and add a polarity switch to the frog. This will be tricky as the point motor is buried under some scenery off to the side and even if I could get to it there wouldn't be enough clearance above it. Also I think I'd have to rip up the track to convert the insulfrog to electrogrog right?

Thanks
Matt
 

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I had this same problem, with a horny tender drive, firstly i put a small piece of insulation tape on the track where it shorted out, that worked untill i cleaned the track, i then removed the center wheels from the tender and reduced the width of the tyre by carefully filling it, and it worked, no more short when traveling across the frogs.
 

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QUOTE (train_depot @ 11 Nov 2008, 01:18) <{POST_SNAPBACK}>I have an old Hornby R376 LMS Class 4P Loco (4-4-0) which is a pretty good runner, especially after I converted it to DCC and reused the smoke pickups as additional power pickups. It will crawl slowly around everywhere on my layout except over my Peco curved insulfrog points. Half the time the middle tender wheel will short across the frog (to the other rail just outside the main rails) which of course stops it dead.

Any ideas how to fix it? I thought of some ideas but I don't really like any of them.

1) Somehow insulate the middle tender wheels with rubber tyres. I don't think they are pickups anyway.
2) Do something to make the middle tender wheels less floppy, they seem really loose.
3) Treat the isulfrogs as electrofrogs and add a polarity switch to the frog. This will be tricky as the point motor is buried under some scenery off to the side and even if I could get to it there wouldn't be enough clearance above it. Also I think I'd have to rip up the track to convert the insulfrog to electrogrog right?

Thanks
Matt

***The problem is the rail is set a little high in the plastic frog and so a wheel can bridge the small gap..

The best answer is to carefully file the metal rail part of the frog tip so its just a fraction lower - takes careful work with a fine file.

The next best and much easier is to paint the tip area of that frog with a little superglue and let dry overnight - it will insulate it. If you don't have superglue, use nail varnish or epoxy - just keep it a thin layer.

regards

Richard
 

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Discussion Starter · #4 ·
QUOTE (Richard Johnson @ 11 Nov 2008, 02:04) <{POST_SNAPBACK}>***The problem is the rail is set a little high in the plastic frog and so a wheel can bridge the small gap..

The best answer is to carefully file the metal rail part of the frog tip so its just a fraction lower - takes careful work with a fine file.

The next best and much easier is to paint the tip area of that frog with a little superglue and let dry overnight - it will insulate it. If you don't have superglue, use nail varnish or epoxy - just keep it a thin layer.

regards

Richard
Either of the two options you suggest is making the insulfrog even more "insulfrog" than before. I guess it will fix the problem but I hate to make it harder for some of my 0-6-0 Tanks to negotiate the points.
 

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QUOTE (train_depot @ 10 Nov 2008, 16:18) <{POST_SNAPBACK}>.. Do something to make the middle tender wheels less floppy, they seem really loose..
If this were my layout and the only vehicle causing this problem was that tender, and that wheel, I would remove the offending wheel, (or wheels if the loco gets turned and can run either way round on the point) and glue in place a dummy plastic wheel with the flange cut off the bottom. Exactly the way Triang Hornby did it on their old style power bogies. It's a bit crude, but it will work.
QUOTE .. Treat the insulfrogs as electrofrogs and add a polarity switch to the frog. This will be tricky as the point motor is buried under some scenery off to the side and even if I could get to it there wouldn't be enough clearance above it. Also I think I'd have to rip up the track to convert the insulfrog to electrofrog right?..
You can convert the point to switched crossing (frog) in situ, if you are able to cut through the rails at four locations, and solder on and run a wire to a switch. It is a fiddle to do, and you really need a rotary cutting tool and small cutting disc, (and maybe a flexi drive if the point is in a really awkward location,) to make a reasonably easy and tidy job of it.

What you do is cut through the switch rails about an inch from the crossing, and through the rail joiners the other side of the crossing. Fill these gaps with epoxy to ensure that the electrical isolation of the crossing is maintained. Solder a wire between the two crossing rails to bond the crossing electrically, and then take this wire to a convenient location to mount a point motor or relay to switch rail supply, wired to operate either in parallel or sequenced with the point motor operation. (I assume from your description there is no easy way to add a switch to the point motor that operates the point.)

What you then have is a point that still has a dead crossing, but switched as though live crossing, so there can be no short circuit if a wheel bridges the crossing rails because they are always on the same supply side. Lot of trouble to go to if it is just the one vehicle that provokes a short.
 

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Discussion Starter · #6 ·
QUOTE (34C @ 12 Nov 2008, 04:35) <{POST_SNAPBACK}>If this were my layout and the only vehicle causing this problem was that tender, and that wheel, I would remove the offending wheel

I have a quite a large collection of inherited tender locomotives that I haven't tested yet so before I decide which way I should go, I guess I should test all of them first.

I've only really had my layout trackwork and electrics finished for a short while so I guess I should consider myself in the tesing phase still and thoroughly check all my rolling stock.
 

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Hi Matt

I had a similar problem with the rear bogie wheels of a A3. I lightly varnished the wheels thereby insulating them from the track, after twelve months still working fine with no short circuits.

Worth a try regards Mike
 

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QUOTE (train_depot @ 12 Nov 2008, 15:58) <{POST_SNAPBACK}>I have a quite a large collection of inherited tender locomotives that I haven't tested yet so before I decide which way I should go, I guess I should test all of them first. ..
If they have the same style Hornby tender drive with the centre idle wheels wobbling about on stub axles, you are going to have plenty more with the same problem. Modifying the point to switched crossing, ( or biting the bullet and replacing with the electrofrog equivalent ) may be the way to go.
 

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Discussion Starter · #9 ·
QUOTE (mikebiggles @ 12 Nov 2008, 10:16) <{POST_SNAPBACK}>I had a similar problem with the rear bogie wheels of a A3. I lightly varnished the wheels thereby insulating them from the track, after twelve months still working fine with no short circuits.
I like the varnish idea, I think I'm going to try that. What kind of varnish did you use? I only have Tamiya acrylic clear gloss and some floor varnish! I'm thinking Humbrol clear gloss enamel might be better.
 

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QUOTE (train_depot @ 13 Nov 2008, 14:05) <{POST_SNAPBACK}>I like the varnish idea, I think I'm going to try that. What kind of varnish did you use? I only have Tamiya acrylic clear gloss and some floor varnish! I'm thinking Humbrol clear gloss enamel might be better.

Hi

I used Humbrol Clear Polyurethane, only because I had it in stock. Polyurethane is very hard wearing, so that may have contributed towards its long term success. But I think any light clear varnish would do the trick.

Regards Mike
 
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