Searchlight signal build?

This forum is dedicated to Riding Scale Railroading with propulsion using other than steam (Hydraulics, diesel engines, gas engines, electric motors, hybrid etc.)

Moderators: Harold_V, WJH

rkcarguy
Posts: 272
Joined: Tue Aug 22, 2017 10:33 am

Re: Searchlight signal build?

Postby rkcarguy » Mon Oct 02, 2017 3:17 pm

Another important note, the relays have a rating of 6 volts minimum and one amp to "trip". So I should have plenty of allowance there using a 12 volt source for voltage drop across the rails/wheels and through any wiring runs to various parts of the RR.
Uploaded a sketch to imageshack.

rkcarguy
Posts: 272
Joined: Tue Aug 22, 2017 10:33 am

Re: Searchlight signal build?

Postby rkcarguy » Thu Oct 05, 2017 11:16 pm

I found some lens material to go between the LED's and the glass that really does the trick, secured them with E6000 and I'll be ready to assemble the rest of the heads once it's cured enough to handle.
I haven't been able to find anything to make the ladders from, TSC's 1x2 mesh is the only thing close but it's 14ga and its too flimsy. I'm going to give aluminum brazing a shot with some 1/8x3/8 strips of plate and 3/16 rounds, and see if I can get that to work.

rkcarguy
Posts: 272
Joined: Tue Aug 22, 2017 10:33 am

Re: Searchlight signal build?

Postby rkcarguy » Mon Oct 16, 2017 11:11 am

All the heads and masts are built for 6 signals. I also built two mid-level single yellow heads for my el-cheapo diverging route indicator light(SP cascade sub style). I'm ladders and sunshades away from having these all done.

User avatar
ChuckHackett-844
Posts: 56
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Searchlight signal build?

Postby ChuckHackett-844 » Fri Oct 27, 2017 1:31 am

BigDumbDinosaur wrote:ABS will last in the short-term, but its main enemy will be heat absorption from the sun.


Hmmm, I injection-mold my signal heads from black ABS plastic. I have found them to be just about indestructible ... out of my first run of 100 a customer broke one but I don't count that because it was due to a large tree falling on it :o

We have been using them for over 7 years in the Florida sun with no ill effects that I can see.

BTW: In the past I have used 10mm high intensity LEDs from SunBright @ 20 ma but I am switching to (more prevalent) 5mm LEDs because they produce the same intensity as the SunBright LEDs which are getting expensive (now about $1 each in quantity 100). The LEDs are mounted behind a Fresnel-like lens (about 5/8" diameter) turned on my CNC lathe. The lens disperses the otherwise blinding LED light pattern nicely. I'll have to make a small change to the LED holder mold but no changes to the printed circuit board because the lead spacing is the same.
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
"By the work, One knows the workman"

User avatar
BigDumbDinosaur
Posts: 524
Joined: Tue Jun 28, 2011 9:19 pm
Location: Midwestern United States

Re: Searchlight signal build?

Postby BigDumbDinosaur » Fri Oct 27, 2017 2:41 am

ChuckHackett-844 wrote:
BigDumbDinosaur wrote:ABS will last in the short-term, but its main enemy will be heat absorption from the sun.

Hmmm, I injection-mold my signal heads from black ABS plastic. I have found them to be just about indestructible ... out of my first run of 100 a customer broke one but I don't count that because it was due to a large tree falling on it :o

Damned trees! :evil:

We have been using them for over 7 years in the Florida sun with no ill effects that I can see.

"Short term" on a typical full-sized railroad is 20 years. :D I've been mostly unimpressed with ABS signal heads in the distant past, but it could be the material formulations have improved.

The signals at our railroad are all steel, except the optics, of course.

abs_3aspect01.jpg
THree-Aspect Block Signal

We were less interested in absolute prototypical appearance than in functionality and durability, especially the latter. A sneaky design goal was that in the event a human stumbling down the right-of-way were to collide with a signal the signal should be none the worse for wear. That design feature was put to the test—once. :D Most everyone now knows that if they walk into a signal it's not going to feel particularly pleasant. :shock:

BTW: In the past I have used 10mm high intensity LEDs from SunBright @ 20 ma but I am switching to (more prevalent) 5mm LEDs because they produce the same intensity as the SunBright LEDs which are getting expensive (now about $1 each in quantity 100). The LEDs are mounted behind a Fresnel-like lens (about 5/8" diameter) turned on my CNC lathe. The lens disperses the otherwise blinding LED light pattern nicely. I'll have to make a small change to the LED holder mold but no changes to the printed circuit board because the lead spacing is the same.

Fifteen years ago as I was working on our signal system design, I cogitated quite a bit on the optics angle. I did consider the design you have, but am not equipped to make the lenses. I cast around quite a bit for a source of ready-made ones in 1 inch diameter but couldn't find anything suitable. When the club finally got to where we were going to move forward on the project the decision was made to use 1 inch diameter LED panel indicators, which operate on 12 VDC without external limiting resistors, are weather-proof, and are clearly visible at 300 feet on a sunny day. As it turned out, the indicators were relatively low in cost compared to everything else involved and have proven themselves after a decade of use.
Science makes it known. Engineering makes it work.

Atkinson_Railroad
Posts: 130
Joined: Mon Jun 08, 2015 6:27 pm
Location: Michigan
Contact:

Re: Searchlight signal build?

Postby Atkinson_Railroad » Fri Oct 27, 2017 8:56 am

Nice looking wayside signal dinosaur. We need more photos of wayside equipment posted.

The maker of this searchlight remains unknown.

The person who constructed it sent me the photos in the 1990s.
Multiple moves and email changes during the time resulted in losing contact with the builder.

It mimics a General Railway Signal type SA searchlight in high detail.
I don’t know what the internal workings consisted of and wish I knew more about it.

I’ve posted the question in the past elsewhere on the Internet quite a while ago and re-ask the question again here.

Does anyone recognize this model or know who may have made it?

John
Attachments
MVC-006F.jpg
MVC-007F.jpg

User avatar
BigDumbDinosaur
Posts: 524
Joined: Tue Jun 28, 2011 9:19 pm
Location: Midwestern United States

Re: Searchlight signal build?

Postby BigDumbDinosaur » Fri Oct 27, 2017 9:24 am

Atkinson_Railroad wrote:Nice looking wayside signal dinosaur.

Thanks!

We need more photos of wayside equipment posted.

Over the years, I've noticed that there is a tendency in this hobby to focus on rolling stock and track, to the detriment of the other parts of a working railroad. :shock:

The maker of this searchlight remains unknown.

That is a nifty-looking model of a signal with which I have had more than passing familiarity.

That said, I would not be willing to commit the time required to model a searchlight or semaphore, especially the latter. A color light signal is far less detailed and at this stage in my life, much easier to fabricate. Also, I have too much to do and not anywhere near enough time in which to do it. I have several major non-work activities that keep me busy, my F7-in-progress being one of them and contraptions such as the one in the below picture being another.

pocv2.1_top_01_resized.gif
Scratch-built computer.
Science makes it known. Engineering makes it work.

rkcarguy
Posts: 272
Joined: Tue Aug 22, 2017 10:33 am

Re: Searchlight signal build?

Postby rkcarguy » Fri Oct 27, 2017 12:04 pm

That signal is well done, looks to be fabricated and galvanized steel, it's also really big, about 1/4 scale I'd guess?
The ladders on these older signals are notoriously skinny, there is one right at a grade crossing downtown near my work, and it must be only 6-8" wide, which translates to only 1" in scale. They recently took it out of service and cut the head off of it, but the rest is still there.
I'm building my searchlight signals to be middle of the road, made of aluminum and grey conduit fittings, and soon to include ladders, to offer some decent detail without spending a fortune. My wallet and my body won't feel too bad if I were to have a derailment and get dumped onto one, I'm out several hours of work which is the most painful part.

Chuck, I have been playing with several different LED's as well. Obviously crowding 3 of them behind ones lens for a searchlight is quite the task. What I am finding is the same 20ma LED's don't have the same intensity in different colors. I had to really dig around for a higher ma yellow LED to get the same output as the red and green ones. I also think that for large clubs compared to small private layouts, the signal brightness selection is something to consider. At a club, operation would likely be only daytime(although I've seen video's of the train mountain guys running in the dark), and these would benefit from a bright signal viewable from several hundred feet away. As my RR will be a "working RR" with fairly short blocks, operated in heavily treed and shaded terrain, and in the dark during the winter, I don't think I want mine too bright. I've come up with some material that offers a small diamond pattern that I'm positioning behind the lens which disperses the light nicely.

BDD, plastics have improved, sadly because they have to. My uncle is the VP for a plastics engineering firm, and says that they've had to improve the products because UV appears to be increasing and it's effects are now bleaching out the old formulations that used to last 10+ years in 2-3. Window tint for instance, is now metalized to combat UV as it was turning a blue/purple shade pretty quickly. Likewise, good paint with a metallic content can be used and if up-kept, can protect plastic for many years. I have found the stuff I'm using works well on the grey plastic conduit and fittings, but doesn't stick well to the white ones which I had to use for the bulb housings for my single yellow light heads at half mast on two of my signals. I'm going to have to scrape it off and use some etching primer and re-spray them. Plastic parts also don't conduct electricity and tend to not build up condensation inside like metal housings do.

I have always been fascinated by the signals, on my first HO scale layout as a kid I remember saving all that allowance, buying a nice brass double headed signal that was like $32, a lot of money for a kid in the 80's! It's things like that, that separate the "tyco train set" from a miniaturized version of the real world.

User avatar
BigDumbDinosaur
Posts: 524
Joined: Tue Jun 28, 2011 9:19 pm
Location: Midwestern United States

Re: Searchlight signal build?

Postby BigDumbDinosaur » Fri Oct 27, 2017 2:59 pm

rkcarguy wrote:That signal is well done, looks to be fabricated and galvanized steel, it's also really big, about 1/4 scale I'd guess?

To which signal are you referring? The signal I illustrated is 1.5 inch scale and is fabricated from mild steel.
Science makes it known. Engineering makes it work.

rkcarguy
Posts: 272
Joined: Tue Aug 22, 2017 10:33 am

Re: Searchlight signal build?

Postby rkcarguy » Fri Oct 27, 2017 3:12 pm

I was referring to that one, it looks bigger than 1.5" scale in the pic. I'd say that's like 1-1/2" round and about a 10" target without anything in the picture to put some scale to it.

User avatar
ChuckHackett-844
Posts: 56
Joined: Wed May 03, 2017 3:54 pm
Location: Tampa, Florida

Re: Searchlight signal build?

Postby ChuckHackett-844 » Fri Oct 27, 2017 9:02 pm

rkcarguy wrote:Chuck, .... What I am finding is the same 20ma LED's don't have the same intensity in different colors. I had to really dig around for a higher ma yellow LED to get the same output as the red and green ones. I also think that for large clubs compared to small private layouts, the signal brightness selection is something to consider. At a club, operation would likely be only daytime(although I've seen video's of the train mountain guys running in the dark), and these would benefit from a bright signal viewable from several hundred feet away. As my RR will be a "working RR" with fairly short blocks, operated in heavily treed and shaded terrain, and in the dark during the winter, I don't think I want mine too bright. I've come up with some material that offers a small diamond pattern that I'm positioning behind the lens which disperses the light nicely.


Yes, I found the same with yellow both in 10mm and 5mm. I connected all three LEDs (red, yellow, and green), darkened the room and shined the signal head on a piece of white paper. As I recall, I drove the yellow to 20 ma and then selected current-limiting resistors to match (by eye) the brightness's. Not scientific, but came out OK.

They are plenty bright in the daytime but a bit bright at night. No-one has yet requested me to activate the night dimming capability of the controller and I've been busy with other things.
Regards,

Chuck Hackett, UP Northern 844, Mich-Cal Shay #2
"By the work, One knows the workman"

rkcarguy
Posts: 272
Joined: Tue Aug 22, 2017 10:33 am

Re: Searchlight signal build?

Postby rkcarguy » Sat Oct 28, 2017 10:02 pm

I finally figured it out and got it working right with the relays.
Hopefully this makes sense. I am using two SPDT relays, so there is two + outputs which are switched between by relay position. The at rest relay output powers the green light indicating the next block is clear. When the first relay is energized, indicating a train in the next block, the relay drops the green and the "energized output" feeds + power INTO the 2nd relay, which it's output at rest is wired to the red light. The 2nd relay is necessary to allow us to also switch the yellow light, and when the 2nd relay is energized, it drops the red for the yellow. But there was a couple problems. A train in the 3rd block away would not set the signal yellow, because the 2nd relay is not energized when there is no red light(no train in the 2nd block) so it just clicks and stays green, so there would be no warning until the train entered the adjacent block and set the light from green straight to red.
The solution turned out to be simple. I added a diode such that switched wire to relay #2(which would be activated by presence of a train in block 3), and would show yellow on the signal, also powers up the relay so it has power to switch. If the train was coming towards the other one, it would cross into block 2 and as soon as the end of it cleared block 3 and is totally on block 2 it sets the signal red for the train in block 1. I've bench tested it and it works:)


Return to “Riding Scale Railroading”

Who is online

Users browsing this forum: No registered users and 5 guests