I’ve got an Oregon Rail Supply 2-track signal bridge kit in HO. I plan to put signal targets on both sides of each track, one side with 3-light targets and the other with 2-light targets. These will be LEDs and will be wired as turnout position indicators using Tortoises.
Do the math, and you come up with 10 LEDs, each with 2 wires. I’ll be doing as much common wiring as possible, but I’ll still need to run a lot of wires from the signal heads, across the bridge and down the supports. I’m hoping to use hollow plastic coffee stirrers, or perhaps thin drinking straws, as conduit for the wires.
How do the rest of you do this sort of wiring? It seems like a lot of wiring to get into a small physical space, and any hints will be appreciated. Thanks.
Oh, and I’d love to see pictures of signal bridges you’ve put on your layout, lights or not.
I did this some years ago with a two target signal bridge but before any Internet. Never thought of pictures.
I used #44 magnet wire. I used bipolar two lead 3mm green/red LED’s and turned down the outside of the LED using a variable drill. Flattened the end of the LED with a file while in the drill chuck.
I used a little Walther’s Goo on my finger tips to bond the wires together into a bundle. I put a different color paint on each end of each wire for matching.
That’s 28 wires - yes, a lot of tiny wires in a small place. 28? 1 common per head, and you will have 8 heads. 1 wire per other LED, and there will be 20 of them. The small magnet wire is your only hope. You would need multiple conduits ifusing something like coffee stirrers, although I wouldn’t doubt a picture of a prototype set up like that wouldn’t also have multiple conduits. Possibly the eastbound signals going down one side with a relay box there and the westbound signals going down the other side with a relay box there.
I have wired a couple of brass signal bridges. I used those little round rings used in jewelry making for wire looms. I soldered them about 1 inch apart down all four legs and across the structure, then threaded the wire through them. I used wire-wrap wire which is insulated 30 gauge soil wire and comes in different colors. Once the heads were in and the wires were run, I masked off the front of the heads and painted the whole bridge, wires included.
I think if you used hollow plastic coffee stirrers, it would make the structure heavy looking. If I was doing a plastic signal bridge, I would cut the hollow plastic coffee stirrers in small sections and glue them on. Letting the wires show does not detract from how it looks. Painting also has a lot to do with how it looks. If you want a silver bridge, paint it flat black first, then paint the silver with a sponge or brush and just paint the outside parts of the structure.
I have also done the plastic Oregon Rail Cantilever signal bridge. I used a 1/8 soft brass tube inside it. I bent the tube to follow the curve and glued it in. It made a good support for the plastic cantilever. Then ran the wires inside the tube.
I did this to a couple of signal bridges. I used very fine stranded wire (28 or 30 ga. as I recall) and housed the wires in heat shrink tubing under the bridge deck. I used a hair dryer, not a heat gun, to soften the heat shrink tubing so it curved without bending. The hair dryer softened the heat shrink tubing without actually shrinking it. The effect, though hardly visible, looks like conduit, and that is the look I was after.
I just picked up four packages of these pre-wired heads from BMLA…(on sale at Walthers for about $22 for a pkg. of two)
I haven’t had a chance to play with them yet but one nice feature is the true yellow which you won’t get with bi-color led’s. There is VERY fine magnet wire coming out of the head so it should be easier to hide. I have used the teflon wire for other signal heads (Oregon) that I’ve made and it is tiny but a bear to strip properly!
I’ll let you know more when I get back to the layout in a day or so…
Something else to consider, Do you have to have each head display all three colors? Often you can get away with red displayed on the middle or bottom head continuously. This would save quite a few wires there…
In the near future we will be doing something similar. We’ll be wiring for Pensy signal heads on a 4 track main. The wire bundle is also a concern and we’ll be routing them down both sides of the signal bridges. Should be interesting for sure.
Those BMLA signals are neat, first time this has been applied to a searchlight type signal, and certainly better than a bicolor LED and playign with the resistors to make a good yellow. But that’s not the type of signal Mr Beasley is doing. In his case,t he suggestion to check the prototype and see if perhaps some of the secondary indications can be hardwired is probaby the best way to reduce the number of wires. If a certain head always had the upper or lower always red, then there’s little sense wiring it for individual control, although that makes a given signal bridge fixed for a certain location - rather than having every one of them built exactly the same. Of course if this is a one-off on the layout anyway… Bottom line is, regardless of how you slice it, there will be lots of wires involved with signals. Should you have the chance, get a look in a prototype relay case. If it’s been updated to modern stuff it looks an awful lot like we do model signals (for actual operating ones anyway) - some circuit boards receive control signals and turn the lamps in the signals on and off in response and according to conditionals.
Thanks to all for your responses. I’ve saved a lot of the excess wires from Miniatronics incandescent bulbs, so I’ll probably start with those. The heat-shrink is a good idea for the conduit, if I can’t get enough wires through a coffee stirrer.
With magnet wire you don’t strip- use a soldering iron with a drop of solder on the tip . Hold the magnet wire in the drop of solder on the tip and it will burn the lacquer insulation off. It will also tin the wire at the same time…
It will not burn away and it is almost stronger than the wire itself! If I use super fine wire strippers it just stretches! I found that scraping one side with a #11 then pull the wire out and trim off the Teflon seems to work.
With a brass signal bridge, couldn’t you just use one wire for the positive and then use the signal bridge for the ground? Or I suppose that would not work with bipolar LEDs?
It would save one wire for each LED, which is a lot in my case. The bridge I’ve got is a plastic model, though. I’m already planning to use as many “common” wires as I can. Since the signals are used as turnout position indicators, red for one track will be green for the other, so that’s another wire saved.
I’ve never worked with magnet wire. It would seem to be a great idea, as the insulation on standard wire provides most of the “bulk” that complicates the wiring. Is it relatively durable, or do I have to worry a lot about scratching the enamel insulation and causing shorts? I can get some at Radio $hack down the road without paying shipping. Does 30-gauge sound about right?
Just 1 wire - the common from all the LEDs would not have to be run to the ground as a wire from each LED - the LED commons would be soldered on the bridge and 1 wire added to the conduit, but if instead you connect it to the brass structure there would be 1 less wire going down the conduits. 20 wires instead of 21. 5 LEDs per signal, between the upper and lower target x 4 signals, and common.
Well with magnet wire the size of the wire will be smaller than the teflon wire. #36 would run most LED’s. It is very small stuff. It is small enough that you sould be able to get a bunch together to look like one conduit pipe. Paint it black and it would look like a pipe.?
Yes I will bet that teflon wire is very hard to strip. Teflon is very tough material
