Monday, February 8, 2016

Scratchbuilt Grade Crossing Signals - Part 1

I’ve never being a well-organized man. While I can plan a lot, most of the time, I act on the spur of the moment. Last Saturday night, when Louis-Marie asked us what he could do on the layout, I jokingly suggested him to design a dirt cheap way to make working grade crossing signals. I was half serious, knowing he could easily put it off, but I didn’t expect it to be done so quickly and with a high level of craftsmanship.

Grade crossing signals and detection systems are notoriously costly. Add raising shipping cost and exchange rate and it can quickly become ludicrous. Worst, out of 6 signals on our layout, 4 are a special kind you can’t find in HO scale. To make 2 working grade crossings it would cost us at least 500$, maybe more…

Here enters Louis-Marie’s creative mind.  He used an old CD-ROM driver to play a custom made CD with looping grade crossing signal sound.  Jérôme handled the sampling and looped seamlessly the sound file so it could run for 74 minutes. This way, we have a correct sound file for a Canadian crossing. The CD-ROM driver was then wired to a speaker. We still have to find a suitable speaker for this purpose. Our mockup wasn’t loud enough and locomotive sound made it impossible to hear.

The next step was to make a 555 module to control the signals’ flashing red LEDs which only took a few minutes with parts from the junk box.

The real signal at Sous-Bois street crossing in Villeneuve (credit: Unknown)

Meanwhile, I scaled down a picture of the real life signal located at Ciment St-Laurent and started to cut and drill brass tubes from scrapped HO components. Engineering had to be extremely precise to get enough clearance for small wires. It was also required to make sure every brass tube would fit others. I didn’t want to rely solely on solder and decided to make tubes connect in each other. I wired the signal before soldering the parts because it would have been impossible otherwise.

Louis-Marie soldered the brass tubes together and assembled LEDs back to back. The level of precision is quite impressive. He also used shrink tube around the LED to hide their back and make a housing against which the black target will seat.  Speaking of target, we found out Kadee red truck spacers are perfect for 3 mm LED!

Finally, we scratchbuilt a custom ladder made of stiff electrical copper wire. It looks complicated, but in fact, making your own ladders out of wire is a piece of cake. With a Dremel cutoff wheel, I sanded down solder blobs and cut to length the soldered rungs. You are better starting off with longer parts, solder them then adjust the final dimension. It’s easier and it yields better results.

At this point, I added a plastic signal base scavenged from an old HO scale grade crossing signal. Seriously, I always thought HO scale signals were oversized, but they are at least S scale!

Finally, we tested the entire system with lights and sound… and it works flawlessly. Total cost: Nothing and it’s closer to prototype than we could have wanted. I shoot a few very crappy movies to show the result.

Now, you may want to ask me how we will operate the signals. Detectors are a no go. We once tried to design a circuit for each crossing and it wasn’t easy. The problem is each grade crossing has multiple tracks and an uneven number on each side to boot. It would require many detectors and it could be hard to wire everything to work flawlessly. Also, switching operations requires that the signals can be turn off depending circumstances.

Thus, we decided to settle on something more low-budget and simpler to operate. Each grade crossing system will be operated with a regular on-off switch controlling the CD-ROM drive and flashing module. To make sure there’s any delay with the sound file when the flashing system start, the CD will play continuously. In fact, the switch will act as a muting device… idem for the lights.

We are actually discussing the possibility to control the signals with two 3-way switches. Each would be located a few feet away from the crossing were a detection unit should be located. The train operator will turn them on when the locomotive will reach this spot and turn them off when the train clear the crossing. In later days, Murray Bay Subdivision telegraph poles only carried detection signal wires. Thus, on the layout, the switch will be located under the last telegraph pole.

The system is not perfect, but there’s a lot of improvement possible later. Making scale signals is relatively easy and rewarding. The cost is also very low and it was only required to buy some brass tube to make more signals. The first signal, which is also the most intricate, took about 2 hours to build at a leisure pace. Making several signals in an assembly line fashion should be a piece of cake.

By the way, the idea of using CD-ROM drive to handle sound files on the layout will be kept for other ambient sound. This includes industrial sounds near the major factory (Donohue and Ciment St-Laurent) and background sounds like river flowing, ducks and wildlife in the more rural parts of the layout in the same fashion Trevor Marshall do with his Port Rowan S Scale layout.


  1. This is really cool, Matthieu! I love how you used parts on hand to make a really nice crossing signal, and I like your low-tech on/off switch solution with the CD-ROM player for sound.

    1. Thanks Steve. It was crazy to come up with a working prototype in a matter of an evening. I'm looking forward to build the remaining signals and start implementing the system.

  2. Hi Matthieu

    Nice crossing signal. Can you provide the parts list for the 555 signal flashing controler and an electrical diagram ?

    I need two of them for my crossing signal near my white birch papier mill on my CN bridge subdivision ( I have a layout been modeling from Port of Quebec to Joffre Yard )

    Nice site and Great ideas


  3. Salut Dany! You can find a diagram by googling "555 alternating flasher". It's a very common design and it requires no special parts. You can find the parts from any electronic suppliers like Accès Électronique or Electromike.

    I hope it helps. Good luck with your layout, this is a very interesting area to model (we did for a while before focussing on Murray Bay Sub).