I mentioned in the previous post about contemplating ordering some of Rapido's Railcrew uncouplers to use on Mt Wilson so that I can have non-permanent uncouplers and trouble-free running.
Before investing a fair chunk of modelling money into postage from Canada, I thought I'd have a go at testing whether I could replicate the same design concept the Railcrew uncoupler uses with a view to building something similar myself. I bought a 6-pack of 12mm x 3mm rare earth magnets from Bunnings and built a quick test bed from some offcuts of timber and tape.
From left to right are two magnets aligned parallel to the track, then a coaster of roughly the same height to create a level area for the track to run over, then two magnets separated from each other by 1mm of tape, and finally two separated by 5mm. I wanted to see if there was much difference in having the magnets further or closer apart.
The first test with the magnets 1mm apart worked well, uncoupling the TRC and MRC from each other.
Same with the next pair, 5mm apart from each other.
And as predicted, the magnets arranged in line with the track didn't uncouple the wagons. They did push the coupler release bar horizontal though!
I'm planning on using cork on Mt Wilson, so I though I would try out putting the cork coaster between the track and magnets. The couplers appeared to be too far away for it to work.
Time then to test out the on/off function of my plan by taping two of the magnets to the coaster and running a few wagons over it. The photos explain the results.
So that works. I've learned that the magnets need to be right under the track to be strong enough to uncouple the wagons, much the same as Rapido suggests for fitting their uncoupler. Now to work out how to make my own. I'm not particularly confident with electrical wiring despite having muddled through it for Rozelle Street, so I don't really want to operate these via servos if I can avoid it. I'd be ok with a push rod or something similar, provided that I can design it so that "off" is with the knob flush against the fascia so that it doesn't get bumped in transit and as a reminder that the uncoupler is active. More thinking required.
In the meantime, I spent a few hours painting today.
Next job will be tracklaying and wiring, and I'll add the roof and lighting after that.
Phil Collins asked after the last blog post I put up if I could post some additional photos of the rear of the model to get an understanding of how that structure is supported and kept straight.
Happy to oblige!
We spent a lot of time lining each of the vertical pieces up with the level before to ensure a 90-degree join before attaching it with screws fed from inside the framework for the middle two, and attaching the outer end uprights to the end of the layout frame.
We then cut a notch in the top of the backboard, and filed and sanded the opening for each vertical brace piece to feed through and attach at the rear, as shown in the photos.
I'm concerned that there's not enough strength in the horizontal pieces supporting the roof of the module to maintain to 90-degree angle over time, so to provide additional bracing and to visually separate the scene from the fiddle yard I'll add a 9mm pine panel at the left-hand end of the module once the track is down, the turnout servos are installed and all of the wiring is finished. You can see in the last photo that all of the parts at the end of the module finish flush to enable this panel to attach easily. On the right-hand end (pictured) I'll add a 9mm pine panel cut into a 'C' shape to brace this end.
My Engineer brother assures me that I've successfully over-engineered this to beyond what it actually needs to be strong (something about clients being pedantic and not trusting physics), so it should provide many years of fun.
As promised, here's the next installment discussing the construction of the my Mount Wilson Layout.
By the end of the Easter long weekend, the layout frame, baseboard, legs, supports, and backboards were connected and we had cut all of the remaining timber. All up, around 20 hours of effort produced this:
Thanks again to my brother for getting this far. Reaching this stage has been quicker than the same phase of construction of Rozelle Street and it's impossible to do by one's self.
I've replicated the baseboard, folding leg and leg bracing design I developed for Rozelle Street, mainly because they work and in three years and two exhibitions I've never had a problem with them.
The biggest change to the design on this layout has been having a fixed backboard and fixed uprights made out of timber instead of aluminium. This is mainly because I want to transport the layout as a in a state that requires as little assembly and disassembly as possible. I couldn't figure out a way to get the uprights holding up the backboard to be permanently fixed to the timber without getting some heavy-duty fastenings around the back, so I've stuck with timber. I'm very aware that paralysis by analysis has preventing me from making a start to some jobs in the past, so the KISS principle is being followed as much as possible.
Once I got the layout home I mocked up the basic track plan to get an idea of how everything looks before I start making irreversible changes to the boards. While I'm painting the boards and until I receive all of the components for the LED light strips, I've decided to leave the roof of the module off, as well as the front pelmet and left-hand side backboard that will also eventually be attached.
Mocking up the layout with the turnouts and rollingstock I'm going to use has given me really useful indications of things that don't come up in the track planning software, like whether the radius of the curve on the platform road needs to be smoothed out so that the MUB set cars won't look toy-like as they arrive into the station. Ultimately the platform will hide the curve from view, but it's worthwhile marking out where everything is.
The other thing I wanted to check was whether the run around is long enough to fit 4x CH or CTS coal hoppers plus a guards van without fouling the adjacant tracks.
So far it looks as though this will worth, and there's still a comfortable 220mm at either end for running a loco around. The 46 class measures just over 180mm long (I've rounded this down and measured over the loco's headstocks), and the soon-to-arrive 85 class measures just over 200mm long (also rounded down and over headstocks). The biggest loco in my fleet will be an 81 class, and while it will clear the nose of the turnout on the headshunt at the far end of the layout on the rare occasions I can find an excuse to bring it out, it's going to be very tight at 230mm long. The 48, 73 and 49 class are all smaller than a 46 and will have no trouble.
Other projects
I'm also currently looking into developing an on/off uncoupler using magnets. Not an electromagnet, but a system of shifting the uncoupling magnet out of the way when not in use. The neodymium magnets I have on Rozelle Street work well, but they are constantly 'on' and can uncouple wagons in the middle of a train as you're trying to drag the completed shunting puzzle out to the fiddle yard. Very embarrassing at exhibitions or when you have friends over to run the layout. At the same time, that spot on the main line is exactly where I want an uncoupler too, particularly for Mount Wilson when operating coal trains.
Rapido Trains developed their RailCrew uncoupler system a few years ago which works on the principle of shifting the magnet off-alignment from the track when you don't want to use the uncoupler. I haven't seen them for sale here in Australia, but here's their promo video in case you haven't heard of this product before either:
The only thing I don't like about the Rapido RailCrew uncoupler design is the LED in the middle of the track, however you could probably paint it black to blend it in with the ballast. I'm sure I can come up with a device that rotates two neodymium magnets to align perpendicular to the sleepers and parallel to the track, controlled by a cog or rod linked to the fascia to achieve the same thing.
I may just end up throwing money at Rapido if it gets too hard, but we'll see.
Haven't figured out how to replicate overhead wires strung from telegraph poles yet either, but that's on the cards too after I've got the track wired and basic scenery down.
Whistle out Next job is to paint the structure so far and then paint the backboard sky blue. I'll get to that job after the Modelling the Railways of NSW convention at Loftus later this month, and will spend the rest of that weekend working on the layout. At the very least, I want to have the painting and lighting installation complete before the June long weekend so that I can make the most of the extra day off tracking and wiring. Blogging will be slow until then but I'll add photos as the layout progresses.
