# Sensors for crossing gates??



## Deane Johnson (Sep 19, 2016)

As I continue to lay plans for a sizable layout, I've begun to focus on control of crossing gates. Nothing looks "railroad" like an operating set of these do.

My concern is sensing the train. I know many are doing it, I just haven't focused on it and discovered the approaches being used. What sort of sensing mechanism is being used effectively.

One thing that concerns me is having the gates stay down a while after the train has passed. Most prototypes I've seen lower well ahead of the train, but raise quickly after it has passed. That means the system has to know which direction the train is coming from, and when it's cleared the crossing.

Any comments to toss in? BTW, I've made a number of modifications to the plan based on the excellent suggestions I've gotten from members of this forum. 

Yes, I over complicate things in a quest for realism.hwell:


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## mikek (Dec 29, 2013)

I've done lots of research and building on crossings. For control both ways, the Paisley crossing control board is very good. You still have to build the crossing. 
I find having separate tracks for each direction is simplest. Otherwise, you have to have two separate controls like 6V6 offers. 6v6 is set up for British rules, with a yellow before the flashing red, slowing down the works for US users.
I developed my own board using Picaxe control chips, but have not built a complete one since I moved to Tennessee recently. I had to do this to get everything I wanted, horn and bell recorder, flashing lights, and gate controls for long or short trains. To have the gates raise up later I can either locate the exit photosensor a bit from the crossing, or delay the action in the Picaxe programming.
My biggest challenge was getting the gate action slow and realistic. Only the Picaxe does that for me. I found that a recording of a crossing bell from the net includes the horn sequence, too. I use a greeting card recorder for that, controlled by the Picaxe. I use a small speaker instead of the one with the recorder, it works fine, all re-wired to run off track power instead of batteries.


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## DonR (Oct 18, 2012)

There are several systems on the market to 'detect'
the trains for crossings and trackside signals.

Some use photo cells, some infra red, and others
use current draw through the rails. There are
plusses and minuses in each.

In addition to those suggested by Mikek, you might
take a look at products of Azatrax.

http://www.azatrax.com/

I don't have any track occupancy detection being used on my
layout at present so I can't comment on the merits
of any system. I have, however, seen crossing signals
and track side signals working the way you expect on
large train show layouts. One such, even has progressive
signals, where when a train passes signal A turning red,
signal be to the rear of the train goes yellow, as signal C
even farther back goes green.

Don


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## Deane Johnson (Sep 19, 2016)

My current plan is with all double track main line. Do I assume correctly that the general usage of such an approach would be for trains to always run in only one direction on each track?


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## time warp (Apr 28, 2016)

My best system is made by Dallee Electronics. It is current sensing and has adjustable parameters, sound, gate and crossbuck outputs. You have to add your own devices, but speaker is included.

I have a photocell triggered one also, works ok but I far prefer the curent sensing one.


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## Patrick1544 (Apr 27, 2013)

Check out logic rail technologies, Grade Crossing Pro.

https://www.logicrailtech.com/


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## Tom_C (Jan 8, 2016)

I recently played with 2 IR systems. One worked OK until I added fake snow and the sensors lost their mind with all the reflective surfaces. The other, Azatrax, works perfectly.

You can have different sensor set ups to do exactly what you want, detect which direction the train is moving, and you can expand the system for multiple tracks at a single crossing, and have it sense direction for all the tracks. You can also choose a break-beam across the track detection, or a 'bounce" beam with the emitter and receiver in the track pointing up and will detect the beam bounced off the bottom of the train cars, which is what I used.

They also have current sensing devices, but I didn't try them.

It's a great system, and the support after the sale is excellent.


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## Patrick1544 (Apr 27, 2013)

Azatrax has a good system, also.


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## DonR (Oct 18, 2012)

Deane Johnson said:


> My current plan is with all double track main line. Do I assume correctly that the general usage of such an approach would be for trains to always run in only one direction on each track?


Generally speaking, on large layouts I've seen,
the tendency is to run Northbound on the Right track
and Southbound on the Left track just as we drive
in the Americas.

However, in actual railroad practice, you see trains
running either direction at times. Sometimes that
is due to an occupied track that must be bypassed.
Other times it may be to provide access to a diverting
track not available from the 'normal' track. There are
likely many other reasons.

You'll notice that there are crossovers on the real
railroad two track mains at regular intervals.

Don


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## Tom_C (Jan 8, 2016)

I looked up the other 2 suggestions in the thread by MikeK and Patrick1544, and they both look like they will do what you ask, but I haven't used it. Here is the link to the Paisley controller: http://home.cogeco.ca/~rpaisley4/AGC11.html#PCB

Looks like the Dallee circuit TimeWarp mentions uses a railgap to control the signal: https://www.dallee.com/PDFs/xingbel.pdf

To cut down a bit on your reading at Azatrax (because there is a lot of information to digest on the Azatrax site) you can control a single signal with 2 tracks, both with standard resolution (direction sensing) if you use an MRX3 controller with 2 MRD1 sensors for expansion. 

See page 2 of the MRX3 instructions: http://www.azatrax.com/install-MRX3.pdf


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## Deane Johnson (Sep 19, 2016)

I really appreciate these posts. As I return to the hobby after a 15 year absence, the electronics have made it a completely different hobby, and certainly a lot more realistic.

The above comments give me some things to think through.

There's also Arduino, but it's more of an experimental effort. My son, who is an electronics guy and programmer feels the entire layout can be run by Arduino including switches, animated devices, LED lighting, crossing gates, etc. I am currently building the Walther's Diesel House and it will have motorized (servo) remote control doors run by Arduino. He's working on the code at this time.


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## Tom_C (Jan 8, 2016)

I'm certain everything could be controlled automatically. There are purest who would probably poopoo that amount of automation, but I'm not one of them  I'd certainly like to be able to run it manually, but having a completely automated setting would be included in my layout.

I currently only do a temporary holiday set up, and it all needs to be completely automatic for hands-free operation... but it's just a small layout so aside from some signal controls there's nothing complicated.


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## CTValleyRR (Jul 26, 2014)

Tom_C said:


> I'm certain everything could be controlled automatically. There are purest who would probably poopoo that amount of automation, but I'm not one of them  I'd certainly like to be able to run it manually, but having a completely automated setting would be included in my layout.
> 
> I currently only do a temporary holiday set up, and it all needs to be completely automatic for hands-free operation... but it's just a small layout so aside from some signal controls there's nothing complicated.


In my book, there is no such thing as a purist who tells someone else what to do on his layout. Those people are called "Interfering Busybodies," or "Jackass" for short. 

Said busybody is free to do whatever he likes on his own layout, but not to "poopoo" your choices.


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## Deane Johnson (Sep 19, 2016)

I originally tried to stick to the steam/diesel transition era, but found there were so many neat newer engines, rolling stock, etc., that I had to decide to just buy things I like and have a mixture.

I'm now adding all the way from steam to diesels that I see the U.P. currently running. I'm lucky in modeling the UP in that they still have pretty much the same paint scheme from beginning to end so things mix fairly well.

My Burlington portion is pretty much confined to the 50's and the old CB&Q that was around when I was growing up living in a CB&Q division point small town.


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## Lemonhawk (Sep 24, 2013)

I agree that it would a lot of fun to automate everything, but once you've done that your done, that was your hobby, the automation. What I like about this hobby is that there are many different tasks and new ideas to try out, and you get to control where you want to direct your energy. What would be the fun of having a push-button that ran everything, all you could do would be to sit and observe, hoping for some massive collision to break up the boredom!


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## Tom_C (Jan 8, 2016)

I've said this in another thread, but for me personally, a lot of the fun is the journey, not the destination. I will spend hour upon hours doing (something) but once I get the task done then I'm done with it.

I used to set up on-line game/servers, and the fun for me was actually configuring them and making them run. Once I got it configured and running then I didn't spend much time playing.

I can see where someone might get a lot of enjoyment doing the automation task, but for some I know that if the goal is to have a train layout then the automation may not be the end of it.


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