Block and crossing signal detection systems

[tristate 33]

I am planning on making my crossing signals and block signals functional soon. I need some recommends on a good detection system that won't break the bank. I'd prefer to go with the type that detects the voltage change in the tracks vs. the photoelectric eye type because I've heard they are sometimes troublesome due to room light conditions. I'm currently useing DC on an HO layout and the block signals are 2 aspect Model Power. Crossing signals are Model Power and Oregon Rail Supply.

 

[Anonymous]

I use the photoeclectric method for my crossing signals, it wouldn't work for block signals, but I have encountered no interference. I actually made the circuit myself, it was VERY cheap, less than the crossing signals themselves. I got everything I needed for the circuit from Radioshack. Just my

[Dave Vollmer]

I have had fantastic luck with products from a company called Logic Rail Technologies:

http://www.logicrailtech.com/

They make crossing and signal systems.  Now, I use the photoelectric type, and I find even with moderate room lighting I have no problems.  That's even with my sensors buried in ballast.  When I use the layout lighting (48" flourescent tubes) it works as well as just having the single room light fixture on.

Don't discount the photocells yet; I find they make wiring a thousand times easier, they're hard to see even in N scale track, and they work reliably.  Here's how I install them for my signal system on my layout:

I added 4 Logic Rail Technologies signal animators to the mainline position light signals; two at LEW tower and two at M tower.  The product description from the manufacturer's website (http://www.logicrailtech.com/) tells it all:

"When the train covers the photocell (included) the signal turns red. When the train clears the photocell the signal turns yellow after a delay (10 or 30 seconds, selectable). After another delay the signal turns green."

Of course, on the Pennsy we don't use red/yellow/green, but we use position lights.  That's OK, because the SAD-3 does bulb-style position lighting such as the NJ International signals I used!  Even better is that they will even support the two horizontal red-style absolute stop aspects such as were installed on the Pennsy after World War II and I've used at Lewisport.  They require no special track wiring; in fact, they operate independent of the track.  No block wiring necessary!  I selected the 10 second delay.

Click on the images to enlarge:

   They come in neat little boxes with everything you need but wire.

Tough decision...  You're going to have to drill through the layout to mount the photocell:  

  

I soldered extra wire to the photocell and covered it with shrink tubing, since my layout base is over 3" thick (foam plus door).

There!  All done!  Well, not quite...  We still need to mount and wire the circuit board...  

   The wiring diagram included with the instructions is very clear.  Clearer than my layout wiring, anyway...  The gray 14 AWG bus wires are my signal bus.  They run off the old Tech II power pack you see there.  I use the DC throttle to control the signal brightness.  This avoids the need for resistors.  Here you see (among other stuff like track bus, cab bus, signal wires, etc.) the two SAD-3 boards for the East Mifflin signals.

Now, we're truly done.  See?  A little ballast and weathering, and you hardly notice the photocell at all!

 

The result?  Happy railroaders, who now feel safer that the signals actually indicate track conditions ahead!  Here my son Jake takes the TT-1 TrucTrain through LEW Interlocking with confidence, having been given a clear home signal:

Wanna see how they work?  Here are two videos (link to YouTube):

M Tower

LEW Tower

[cacole]

I use the Logic Rails Technologies Grade Crossing Pro circuit board with infrared side-looking emitters and detectors pointed across the track and disguised as posts.  By using infrared there's no problem with overhead light, or lack thereof.

[ereimer]

nice tutorial and demo video Dave , thanks !

 

[SMassey]

If you are ever planning on night ops with subdued or no lighting at all then you dont want to go with photoelectric, I should not need to say why.  Now what I have found that works really well in all situations is InfraRed.  The sensors can be hidden in a bush or tree that is trackside and will work in day or night conditions.  The transmitter and reciever diodes are simply LEDs and usually come in 5mm or 3 mm sizes.  I cant find the link to the company that I found that makes the circuits for this setup but I do remember that the stuff was really cheap.  I will ask one of my friends if he knows the site he is after all using the same system I am thinking of on his layout.  He uses the infrared for signaling and also for detecting where a loco is on his staging tracks so we dont foul a switch when we go to park.

 

 

[Texas Zepher]

I need some recommends on a good detection system that won't break the bank. I'd prefer to go with the type that detects the voltage change in the tracks

  It is hard to beat the simple twin-T detector.  Simple to build, simple to hook up. They can be built cheaply and in quantities with parts from Radio-Shack.

See the link below.  About 3/4 the way down the page. 
http://homepages.paradise.net.nz/~rdmurg/clinic/detectit.htm

[dinwitty]

Bruce chubbs detector is good I think you can buy them or makem also if you wanna.

 

For crossings just go ahead and lay in the detectors, then pick the detect you need for signals/crossing isolating with diodes to prevent cross detecting.

 

[tristate 33]

Thanks for all your responses. The photo cell method does look good. I like the minimum of wiring involved.