Greenwich Couplings

[B.Meldon]

Thank you Darren for taking the time to answer my questions, it is indeed a great help.

I can see from your photo of the electromagnet exactly what you are on about now. Having briefly spoken to someone else I realise that these are the

[cnw6847]

Hello, 

I am new to 009 and just started looking at rolling stock. Having being used to KD couplings on my HO stock I thought I would go for Greenwich couplings so I could have some hands off uncoupling. Micro trains and Dapol couplings just seem a bit pricey.

For my HO stock I use non magnetic wheelsets so not to get steel axles attracting on the magnets, I notice the Greenwich magnets are quite small, is this likely to be a problem?

I have put some Graham Farish/Bachmann metal wheelsets in my peco wagons.

Thanks

Richard

[Krizzy]

The Greenwich button magnets can be a problem with very small lightweight wagons fitted with steel wheels and/or axles, eg the old Minitrains rtr mines trucks. They often tip up when moving over the magnet. Most of the larger wagons like W&L opens on my layout are fine if fitted with metal wheels and/or axles.

Roger

[cnw6847]

Thanks Roger, I will try and weight the wagons if possible, which hopefully will help a bit.

[DeadHorse]

If I were to fit magnetic uncoupling on a layout I built, I would arrange a lever system to raise the magnet into position under the track (in a hole or slot covered with paper + ballast) rather than have a fixed magnet permanently in place.
As it is, I dont exhibit, so part of my shunting enjoyment involves using a scale 30ft pole held between a monster pair of digits.

[Darren Hedges]

I have just fitted the remote uncoupling onto Pont Gelert.

I didn't want to fit electro-magnets this time so I opted for different methods, fixed permanent magnets (Greenwich) and tufts.

As Roger has already said the small yet powerful Greenwich magnets can be a problem with small wagons and/or metal axles so I decided to approach the problem from a different angle, quite literally.

Rather than fix the magnets horizontally (flat) I've fitted them vertically instead (upright). By doing this the attractive forces from above are much reduced as the magnetic field is mostly directed sideways rather than upwards. The force is sufficient to attract the soft iron wire wound onto the tail of the Greenwich couplings but not enough to attract steel axles or wagon weights. There's probably a much more scientific explanation for this effect, but if there is I don't know it. An added bonus is that they don't need to be buried anywhere near as deep.

So far test running has shown this system to work reliably, but time and more testing will be needed.

The other method (tufts) is that used by Roger Nicholls on his many exhibition layouts. This is simply a tuft of woodland scenics tall grass fibres glued into a hole located along the track centreline. the fibres are then cut to length when the glue has dried.

When a vehicle is propelled over a tuft the dropper used for magnetic operation catch's on the tuft and lifts the loop. When a vehicle is drawn over the tuft the dropper simply passes through the tuft and is unaffected.

Unfortunately, experiments have shown that this method does not work where the locomotive draws a vehicle over the tuft, this is why I have also had to fit 2 magnets, one on the platform road where the loco uncouples from the coaches and one in the loop where the goods engines uncouple from it's train to run round before it starts to shunt.

We will see how well these 2 work.

Regards,
Darren.

[rod335]

Maybe it's just me being clumsy but I found it very difficult to wind the iron wire round to tail of the Greenwich coupling for magnetic operation. At least difficult to do it neatly! In the end, I soldered the cut-off length of the Peco track pin used as a pivot down the side of the tail. Worked perfectly and a lot quicker whilst not being really noticeable. I use the past tense as I don't use these couplings anymore, not because there is anything wrong with them, just don't need automatic operation anymore.

Rod

[Krizzy]

I have never had a problem with the soft iron wire. I wind the wire round the tip of fine pointed tweezers 6 or 7 times before fitting onto the coupling's tail. Secured with some superglue and then cut off the remaining wire.

Roger

[Darren Hedges]

I have never had a problem with the soft iron wire. I wind the wire round the tip of fine pointed tweezers 6 or 7 times before fitting onto the coupling's tail. Secured with some superglue and then cut off the remaining wire.

Roger

I agree with Roger, I fit the soft iron wire slightly differently but still never had a problem.

If anyone has problems winding the soft iron wire on to the coupling loops tail, try winding it on before folding up.

Simply mark where the tail will be folded using the guide marks etched into the fret, then remove loop from fret and wind wire onto tail making sure it is clear of your folding mark. Secure with a drop of superglue. When dry fold up the loop and bend the tail at your mark.

Regards,
Darren.