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Bachmann coaches - close coupling system


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Firstly, the process I am about to describe and share with you, I can take no credit for - I am just passing it on, as it seems to be working for me. The original article that I have taken the information from is in Traction Magazine, issue 204 (currently on the shelves of newsagents). Not necessarily known as a modellers magazine, it often contains many interesting photos from the past which are useful to those of us who model our own particular "golden era". It also contains a small modelling section.

As most of us will be aware, British outline Bachmann OO coaches come supplied with an alternative close coupling, to use instead of the tension lock couplings, as fitted. The coupling looks like the air / vacuum pipes seen between rolling stock, with NEM prongs at each end. I fitted these close couplings to my coaching stock and was very impressed with the superb effect in minimising the gaps between vehicles they give. I was even more delighted to find that they also worked around my sharp curves, with no buffer locking being encountered. There is only a slight problem in their use however.

In order to fit the close coupling, both coaches need to be laid on their side, to get the prongs into the NEM pocket. To remove the coupling, the same needs to be done and, ideally, a pair of pliers needs to be used to squeeze the prongs together, to free them from the NEM pocket. You can tug them out of the pocket, but this carries an obvious risk of breaking something. Imagine fitting a rake of 10 or 13 coaches together like this and then trying to roll the coaches over to get them upright and onto the track! Its tricky :? If you are in a position to only have to do this once and your rake of coaches stays together on your railway, then its not a great hassle. Like many others here, I am sure, my stock lives in stock boxes and has to be coupled up and uncoupled for each operating session. I quickly saw that this time consuming and tricky practice of coupling and uncoupling, could a) end up damaging the NEM pockets & couplings and b) risk damage to the finish of my coaches. Hopefully, this modification to the Bachmann close coupling, will mean that this is a thing of the past and we can have our proverbial cake and eat it :D

To do this simple modification, you will need the following items :

A Bachmann close coupling bar.

Super strong magnets, 3mm diameter x 1.5mm thick. (Available very cheaply on EBay & internet. I used EBay and paid £1.99 for 50)

Strong adhesive (I used Javis scenics Cyanoacrylate).

Below is a photo showing the couplings at various stages in the process and fitted to the coach - hopefully you will be able to follow my commentary in line with the photo.

 

couple.JPG

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Looks very interesting (and for me and my eyes, very fiddly!) But with the problems I've had with this type of coupling in the past I'd be willing to try anything.

I've used the 'pipe' couplings with some success in the past but as you correctly mention, they are the devil to couple and uncouple. The magnets would seem a great way to overcome the problems associated with removing stock so fitted from the track on a regular or frequent basis. I see that most types of mini magnets have a 'pull' rating and wondered how that rating compares to actual operational use. How many coaches have you fitted and run in a single rake? I imagine that gradients would also need taking into account?

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This is my kind of idea, mainly because if it doesn't work I can simply return to tension locks. I may give it a go.

I wonder how long it will be before someone brings out a range of these. A set that look like a modern DMU coupling would be very attractive to me.

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Mick

To answer your question about pull ratings, the answer is - I dont honestly know as I havent tried yet :!::oops: Its been too blasted wet :evil: The guy who wrote the article reckoned on upto 10 coaches - and I think that was all he wanted to do - so it could be more. Personally, my maximum length is normally 9 coaches.

Roll on some finer weather and i will give them a try - and with some new sounds too ;);)

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Nice mod but too fiddely for me so will be sticking with the pipework connection. Mine seem to spend more time in boxes at present so the hassle of connecting up only happens once in a blue moon.

Ian

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Hornby R8220 close couplings will close couple Bachmann coaches very effectively.

Although they are actually too short and when fitted so they don't automatically couple when pushed together unless each coach is lifted slightly.

I adapted a pair of tweezers which can be slid under the couplings and squeezed to lock them together.

I may try the magnet system too though, it will be something to do on these long wet summer days!

Tweezers.JPG.dc8579225afecf72d2da018944429344.JPG

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I have conducted an initial "pull" test today, with the set of coaches I have so far converted to the magnetic couplings. The set of 6 Bachmann mk1' performed very well, with no buffer locking or problems with uncoupling. This was on my inner running line, which whilst not going up the serious, sharp, incline that the outer line goes up, it does go round the tightest curves. The train can be seen running on my latest YouTube upload (running behind the 7F).

In about 3 months time, when we have the next dry day :lol:, I will try a few more coaches and see how that goes.

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  • 2 weeks later...

This post is great. I have a 12 rake of Pullmans that always derail. So, taking the spare pipe couplers, I found that they also fit the Pullman NEM sockets on 8 of the 12 (the other four have a weird coupler screwed in).

Just waiting for some sun to test it out....

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The dummy pipe couplers and the Hornby R8220 couplers mentioned by IanR both provide a rigid coupling and are a massive improvement over the standard tension lock coupling fitted to these type of coaches. However, you may continue to experience derailments when hauling a large number of coaches around anything but large radius curves because the weight of the trailing vehicles restricts the movement of the cam type coupling.

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A further update on load testing the magnetic coupling conversion.

I completed another batch of couplings last night (not as good as the first batch - ie not so square :oops: but useable) with a view to do some serious load testing on the magnets.

Before I run through the loads I tried, you have to appreciate that my railway / track is pretty rough, full of humps and bumps, as well as having some seriously tight curves - I think the tightest is just under 2nd radius set-track :o - and its through the full 180 degrees :o I think anything I can achieve, will come a lot easier to you guys who run on billiard tables :!::lol:

Not wanting to be too conventional (or boring) and in the interest of science, I went pretty much the whole hog straight away :lol:

My Bachmann chassised class 45 and a mixture of 15 mk1 & mk2 coaches. Firstly, the loco had no trouble in pulling this heavy load all the way around my line - up and down the bumps and around the curves, but the tightest curve proved too much for the couplings and one parted :roll: . I reduced the load down to 12 coaches, looking at any magnets which werent making a good contact with each other, and this load was succesfully hauled around :) . (This was later improved upon - the Hornby class 50 struggled with load 13, but the whole set went around without parting or derailing. :D)

Wary of other peoples comments about the haulage capacity of steam locos, I did try my 7F with load 12 :lol: . Unsurprisingly, it didnt like it at all :lol: I took it down to load 9, with which it struggled but managed to work around the layout. I concluded that load 8 will be the maximum for this loco.

After the 7F, I set my Heljan 33/0 to work on a load of 11 or 12 (cant remember now - its says on the video caption if you take a look), which it managed to pull with no problems at all. Similarly the Hornby class 50 and Bachmann class 47 handled this train ok. All 3 of these locos were tested with a magnetic coupling inserted into their NEM pocket, so the whole train was coupled using the magnetic couplings.

Overall, I am very pleased with the strength of the magnets, but not so with my sub-standard conversion work :oops::lol:

Hopefully, below, will be a link to the video on YT, of the days tests

Happy days :D

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Well it's clearly been a success Iain - that's good to see. I assume that the running session experienced fewer derailments than when using the standard couplings? When you say that the couplings parted on the curves, which coach (or coaches) was that - where about's in the train did they part? Was it a track radius problem or a trailing weight one?

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Mick

As it was in the middle of the train, I think it was mainly down to poor magnet alignment - ie I had not glued the magnet onto the end of the pipes straight and it wasnt sitting flush against its neighbour :oops: If the workmanship had been better, who knows what I might have been able to pull :lol:

I only experienced a couple of derailments, which bearing in mind the undulations and sharp curves in my track, is pretty good. One of the vehicles involved seems to be a repeat offender, if you put it in the front or middle of a long train. Where it is normally positioned in a short, 5 coach train, it isnt a problem. The other vehicle was a very light, BG full brake. Again, only a problem if it is in the front or middle of the train - when at the rear, in ran around fine.

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  • 3 months later...

I like this idea and searched the Bay for magnets .. Came across these which could be used with a 1mm rod in 1 magnet, locating in the 1mm hole in its partner - A little more expensive but might make alignment more positive .... :?:

http://www.ebay.co.uk/itm/Pack-of-25-very-small-Neodymium-ring-magnets-3mm-dia-x-1mm-dia-x-1mm-N35-grade-/130650106975?pt=UK_Collectables_WeirdStuff_RL&hash=item1e6b5a6c5f

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  • 2 weeks later...

I read this series of posts with great interest, as I have been experimenting with different methods of coupling coaches, and also with the use of these high-strength magnets for various purposes. I have also carried out tests and calculations to establish the force required to pull trains up the 1 in 50 gradients on my railway, which showed that the force required from the locomotive for 12 coaches of average weight 150g up a 1 in 50 gradient is about 50g. This is beyond most RTR 00 steam locos, but for modern RTR diesels it is no problem.

Using 2mm dia x 2mm N42 NdFeB + NiCuNi magnets from Magnet Expert, I lifted gradually increasing weights, and 55g was the highest that held reliably. This was with a sheet of gummed paper between the magnets to attach one to the weights. The other was glued to the end of a shunter's pole.

So with a straight pull, 12 coaches up 1 n 50 is feasible. In practice, there will be misalignment, shear forces, and shock loads to contend with, so a stronger magnet would be desirable. But it's close enough that I shall certainly carry out further experiments.

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I now have some 3mm dia x 2mm neodymium magnets with a specified 250g in-line parting force and 50g shear parting force. All I need now is the glue to hold them to the Bachmann plastic firmly enough. Araldite ultra-strong epoxy and Loctite 480 cyanoacrylate don't do it! My next attempt will try glue inside 3mm I.D. heatshrink sleeving, which is on order.

Two hours later, I have found some 4mm heatshrink and some Loctite 406 (for plastic & rubber), and bodged together a pair of magnetic couplers. They are badly made, and the magnets don't make good face-to-face contact, but I'll try them anyway. One goes on a loco, the other on a coach, and they are coupled together. The other end of the coach has the cord attached for my pulling force test rig. The weight is increased up to 87g, which is equivalent to pulling 25 150g coaches up a 1 in 50 gradient. I shake the coach and the weights to give a bit of shock loading, and still the magnets hold.

I would still like to try it under real running conditions when the weather improves, but I am now more than confident that the technique will work with plenty in reserve, providing I can find a successful method of attaching the magnet to the remainder of the coupling.

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I now believe I have a method of fixing the magnet to the plastic "pipe" that will hold when the couplings are repeatedly pulled apart to separate the coaches. I first glue the magnet and pipe together, in the same way that Ba14eagle described in the first post. I then slide a 5mm length of 3mm ID 3:1 heatshrink sleeve over the joint. Squeeze in a little superglue, shrink the sleeve, and hey presto! It's done! There's a picture below of a pair coupled up.

121127-2002.jpg.8cb301336621001e672ea230d04422be.jpg

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Tidy Job, Ian. I look forward to seeing how this works out.

I'm lucky enough :?:8-) to be one of those "perfectionists" who marshall their coaching stock rakes in the same way each session - they are even put the correct way around in the stock tray, so others can put them on, the right way around, every time :oops::oops: .

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Is the plastic pipe section that you have attached the magnet and heat shrink to, the original pipe coupling that is included in the box as an alternative to the standard tension lock? I assume if it is that you have cut it in half before attaching the magnets? This then gives you the close coupling qualities of the alternative pipe coupling, retains the ability to negotiate sharper curves, and an easier means of coupling/uncoupling?

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