First time scratch build - N scale BC Hydro Rail caboose

[peteski]

Ouch!  Yes, always be vigilant when it comes to Tantalum caps.  I'm really surprised that even with the 2.7k resistor limiting the charging current, then cap burned up. If that cap was used in a keep-alive circuit, hooked up directly to 12V, it would have probably self-destructed in even more spectacular fashion (as in a mini-explosion).

As far as slowing down the flash rate, why can't you leave a single cap but increase the value of the resistor?  Maybe 3.3k?

I also might have missed something.  Do you have 3 LEDs in series, connected between the collector of the transistor and ground?  So each flasher drives 3 LEDs?
I thought the caboose had only 2 marker lights (2 LEDs), one on each flasher circuit.

[craigolio1]

Ouch!  Yes, always be vigilant when it comes to Tantalum caps.  I'm really surprised that even with the 2.7k resistor limiting the charging current, then cap burned up. If that cap was used in a keep-alive circuit, hooked up directly to 12V, it would have probably self-destructed in even more spectacular fashion (as in a mini-explosion).

As far as slowing down the flash rate, why can't you leave a single cap but increase the value of the resistor?  Maybe 3.3k?

I also might have missed something.  Do you have 3 LEDs in series, connected between the collector of the transistor and ground?  So each flasher drives 3 LEDs?
I thought the caboose had only 2 marker lights (2 LEDs), one on each flasher circuit.

I wonder if it was getting the full 12v. At the time it blew it was connected to power via the constant lighting circuit, but I had no LEDs running. So it was sitting there fully charged.

In previous tests I had tried a 3.3k resistor but it changed the style of the light flash as well. It ramped up really slowly and then winked. Almost like a lighthouse. Anything more than 3.3k and the LED was on solid all
The time.  I was after more of a strobe effect and got that with 2.7k. Doubling the value for the caps slowed down the flash just enough.

This project has two of the same circuits each running a single LED.

I made a bit more progress today. I’m using Kato caboose trucks for pick up. Wires soldered to the insides of the truck pass up through a hollowed put MT truck pin.







I discovered that these wires were too stiff and caused the trucks to not sit right. Anticipating that this would cause tracking issues once I put the circuits and shell on, I opted to swap them out for magnet wires. This worked fine. Then I learned that the circuit was just a hair too tall for the body to settle down on the under frame. After the below image was taken I siliconed the package to the underframe and tested the body but it wouldn’t fit.



So I moved the two extra caps to the outside.



It’s hideous. Haha. But it’s working great, tracks well, has no flicker.... and is not on fire.

The next step is to install the marker lights themselves.

Craig

[CNR5529]

.... and is not on fire.

 

I know, I know, BCOL vs BCH... but I'm guessing they didn't test their caps either? 

[craigolio1]

 

I know, I know, BCOL vs BCH... but I'm guessing they didn't test their caps either? 

Eek!   Very funny. Verrrry funny.

[craigolio1]

The final step on his project is to mount the lights under the rear platform roof. On the prototype the lights are hanging from two brackets at the outside edge of the roof.

I used some left over brass sprue of the right shape to make the brackets. These lights are beyond fragile and I didn’t want them hanging on by the lens, so I soldered a small brass strip to which I could later mount the lights.



This serves as a convenient handle to allow me to grip the parts during installation.  I drilled holes through the end of the roof. The parts were trimmed and test fit, and glued in place.  After they were glue in place I trimmed them to fit.



The lights were attached using Bondic which, if you haven’t tried it, is really slick. Once stuck to the front of the mount I wrapped the brass with a tiny bit of epoxy so that the assembly really had a good grip. I haven’t been too rough with it but it feels quite sturdy.



With the lights installed I moved to final assembly. I stuck weights on the inside of the end walls, and soldered the wires to the circuit. The body is secured with drops of tacky glue in each corner.

All that was left was final testing and painting.

The light housings were painted silver and then orange. And I used some of my custom mixed blue to touch up the holes that I filled in the ends of the roof.



I also installed MT 903 Z scale couplers.



And here is a video of the completed lights in action.

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It feels great to actually finish this project. The lighting was something I had thought about for a long time and with the availability now of 0201 LEDs I feel a whole new level of lighting detail is possible.
Thanks for following.

Craig.

[CNR5529]

Man, that turned out incredible! I've said it before and I'll say it again, the wizardry you are capable of with tiny LEDs is next level.

[craigolio1]

Man, that turned out incredible! I've said it before and I'll say it again, the wizardry you are capable of with tiny LEDs is next level.

Thank you.

[Ed Kapuscinski]

Those are the same flashers that Conrail used. I've always wanted to add them to some cars. Hmm...

[peteski]

Those are the same flashers that Conrail used. I've always wanted to add them to some cars. Hmm...

They used highway flashers instead of FREDs? Or was that before FREDs?

[craigolio1]

Was definitely before Fred’s as the caboose was still staffed. Guess they just wanted visible markers and these were probably super cheap

[peteski]

That makes sense.
Also, all the highway flashers I have seen in construction zones were flashing amber. So red flashers must have been used elsewhere (and on cabooses).