fungus

I have just logged on and was horrified to find that my last post was before Christmas! What has happened to the first four months of the year? Well, without going into details, I can at least truthfully say that I have done some work on the garden railway! Jobs done or in progress this year are: •Routine maintenance •Extension round the corner from the railway boundary to the neighbour's boundary •Complete automation of removable crossover module •Re-ballast, wire, signal and automate the viaduct •Get the railway wi-fi control network working reliably •Install a power bus and connect to track at reasonable intervals. Jobs needed but not done: •Too many to list. For further details and pictures, see http://fungusmodels.blogspot.co.uk/" onclick="window.open(this.href);return false;

The speed is impressive! Why did we develop Eurostar, when we could have used A3s and teak coaches?

It's good to see you are getting some successful winter running.

Sounds useful. I found Loctite 480 good, ordinary araldite didn't hold.

The curves look good, but it's not all good news! There is also a 1 in 50 gradient here, and it was quite a challenge to get it (almost) right. Part of this stretch had to be relaid because I didn't measure the gradient accurately enough during construction, and trains were stalling where it got steeper than 1 in 50. When I watch a train snaking around the reverse curves now, I think that the effort was all worthwhile!

Perhaps all that would be needed would be to reverse the current through the coil of the electromagnet. I'd need to find some of my old physics text-books before saying any more!

IMPORTANT NOTES One of the best ways to kill a good idea is to not define stadards early on, so that everyone does it slightly differently, and no two systems can work together. Examples include VHS & Betamax, mobile phone chargers, and many more. There is one critical parameter of the DOGRF Mk.2 coupling that I haven't yet defined and will now attempt to do so. For two couplings to mate correctly, they must both have their N and S poles in the same orientation, so that on mating, N attracts S and S attracts N. Having made about a dozen of these couplings now to an arbitrary standard, I have measured which are the N and S poles and will define this as THE DOGRF Mk.2 magnetic coupling standard. In that way, any couplings you make will work with anyone else's, and vice versa. The tools you need are an ordinary magnetic compass (and no, a GPS receiver won't work unless it includes a nagnetic compass), and a bar magnet (one of the magnets you are using for the coupling will do). Glue your magnet to the end of a non-magnetic stick with the line between N and S in line with the stick. (If you are using the same magnets I did, then one of the two flat faces is glued to the stick.) Point the magnet end of the stick at the compass, and move it all the way round the compass. If the red (N) end of the compass needle points to your stick, then we will say that your stick ends in a N pole. If the red (N) end of the compass needle points away from your stick, then your stick ends in a S pole. Mark your stick with either S or N at the magnet end, and the opposite at the other end. You can now use the magnet end of your stick to check the polarity of any coupling or magnet, bearing in mind that N and S are attracted, and N and N or S and S are repelled. Couplings can also be checked by ensuring they mate correctly with a known good one. A known good one can also be used to hold a new pair of magnets in position while they are glued to their "pipes". I will try to add some photos to make this clearer. And which way round should the coupling magnets be? When looking at the end of a vehicle on the rails with a coupling fitted, the mating face of the right-hand coupling magnet should have its N pole toward you. Finally, a VERY IMPORTANT SAFETY WARNING. If you bought your magnets from a reputable dealed, you will have been given some dire warnings. It is worth reiterating that these tiny magnets can cause life-threatening injuries if accidentally swallowed. So keep them in their original packaging until assembled, and don't leave them laying on the work bench. And don't fit them to anything that could be used by children. If you pass them to anyone else, also pass on the warnings too. It's all common sense really, but so easy to forget, with potentially serious consequences.

That's the one.

I spent a couple of hours today, despite the freezing weather, preparing a length of garden track and running a 12-coach test train round the reverse curves on a 1 in 50 gradient. This was the first fully "live" trial of the "DOGRF* Magnetic Coupling".

I spent a couple of hours today, despite the freezing weather, preparing a length of garden track and running a 12-coach test train round the reverse curves on a 1 in 50 gradient. This was the first fully "live" trial of the "DOGRF* Magnetic Coupling" (see topic "Bachmann coaches - close coupling system" in this Forum). The couplings between coaches 1, 2, 3, 4, 5 and 6 were to the Mk.1 design using a single 3mm x 2mm magnet on each coupling. The couplings between the loco and the first coach, which were taking the greatest load, were Mk.2, with an opposite-polarity pair of 2mm x 2mm magnets. None of the couplings failed during the trials, which comprised several low-speed runs up and down the test track. (Higher speeds were not possible this time because of limitations in the control equipment, i.e. it couldn't supply enough current for a Hornby class 50 pulling 12 coaches up 1 in 50 at more than a scale 20mph.)

Thanks for the good wishes, guys.

Very labour-intensive; I don't think you'd like the price! Once the design is proven however, perhaps I should hand it over to a production team, who would probably get it made in China for tuppence.

I've tested a pair of double-magnet couplings (which we'll call Mk.2, the single-magnet version being Mk.1), and they were still holding strongly at 190g! That's amost twice what my strongest loco can pull before the wheels start to slip. (Note that 190g is the horizontal force in line with the loco, or the weight it could lift or support using a horizontal cord running over a pulley. It is not the total weight of the train it could pull, which is much greater.) I'll post a full report when I have some pictures. The advantages of this design over the single-magnet (Mk.1) version are: - All couplings are identical and interchangeable - Smaller magnets - looks neater in side view I have also devised a simple production method which automatically holds the pairs of magnets in exactly the right orientation for assembly, without the need for any special jigs. Again, a report will follow when I have some pictures. Further developments? Well, a better design is still needed for fitting to locos. And it's possible that an even smaller magnet would still give enough strength for our purposes. Watch this space!

Yes, I've just done the same thing while I've been making up my "magnetic couplings test train" (photos will be taken and report written!) ready for the next warm, dry day with no other commitments. My indoor layout is only 5' long, so a train of 12+ coaches has to be assembled and checked a few coaches at a time.

By the way, Iain, I was trained as a scientist and had a long career as an engineer, so you are quite correct, but I'm afraid that the scientists' way of working is ingrained in me! In fact, solving probems to eventually achieve an objective is what keeps me interested in the hobby.

You're exactly right, Mick. It's the original plastic pipes from the box, with 4mm removed from the middle to allow for two 2mm long magnets. I have also made some now using other material for the pipes, but that's another story! I am also making a pair of couplings as an experiment, using two smaller magnets with opposite poles outward, one on each pipe. If it works, it will have the advantage that the couplings on all vehicles will be identical, and both ends of the vehicles will be identical, so vehicles can be turned around and moved without changing the couplings. I'll report on this when I've tested it.

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.

Sometimes the best approach, before you get too attached to it!

At least it has given us plenty of time to work on the locos and rolling stock, Mick. However, after a while that's little consolation if you can't run them. Ian

A good selection of fine locos Ian, and your weathering is exemplary! The next section of my railway will be between 2ft and 3ft above the ground and I am in the process of deciding on the best way to proect it from the weather so that I can add some scenery. The rest of the railway had been close to the ground and the scenery has been the garden. So I shall be looking carefully through your earlier pictures for ideas! Ian

Hello, Matt, and welcome to the club. Mick is right, gradients do add another level of complexity to the design of the railway. However, I decided that in my case it was worth the effort to get the track at a preferred height above ground in each area of the garden, given the existing slope, and it has worked out well. I have limited the gradients to a maximum of 1 in 50, which provides a challenge on trains over about 8 coaches for the less able steam locos, but is no problem for most of the diesels, on trains of 12 coaches or more. If you would like to see what I've done, you will find some pictures in this forum under Danes Wood, or the link to my blog is at the end of this message. Good luck! Ian

Most impressive, Nige. Were the outdoor photos taken over the course of constuction, or do you dismantle it in sections?

Don't give up yet!!! The recent high winds have cleared all the trees of leaves in our garden, so as soon as I can I'll be out there sweeping them up. By the way, Andrew, last week I had the planned visit to the locomotive works for corrective maintenance, and everything now seems to be in perfect working order (touch wood)! It will soon be time to plan the next exchange visit (perhaps to show off anything that Father Christmas brings?). Ian

I've now returned to my "home shed" from the human equivalent of the locomotive works, after a year of major repairs to some of my key components. Perhaps if the weather improves in the Spring, I will be able to spend more time on building the garden railway!