Relay recommendations

Do you intend to have one lamp for each of the the three sidings, in other words three green lamps, to go with your planned red one, or will you have one only one green (and have it represent all three sidings)?

Mike

Three double pole double throw relays.  Wire the red to the NC, normally closed terminals, and green to the NO, normally open, terminals.

Not sure why you need DPDT for this, a single pole will do the job just fine.

@Conductor Earl posted:

Three double pole double throw relays.  Wire the red to the NC, normally closed terminals, and green to the NO, normally open, terminals.

Earl,

To what do we wire the coils for these three relays?  I'm thinking one wire from each to each of the center rails of the sidings and the other wire from each all tied together on the common (outside rail that goes to the transformer).

Also, thinking about whether these tracks carry conventionally-controlled or command-controlled trains.  With this scenario the relays will not always be fed with enough voltage to operate correctly if conventionally-controlled (depending on the position of the throttle). 

Mike

For clarity, the three individual tracks are part of a loop, all through tracks that merge onto a single track that passes through a wall.  That single track already has a signal that displays red so i don't send something down that line if the track is occupied.   I would like to have the signal head be green when the track is powered, red when it is not.  I know how to set this up and have the necessary lights to make this work.  I run tmcc so all command control.  My confusion in selecting a relay is what to purchase meaning what is out there where the coils can be powered by 18v ac?  Or do i find something where the coils are dc powered and just place a bridge rectifier in the mix.  I know those who live in the world of electrons might find my question kindergarten like but this is not my world.  Just would like a recommendation before i buy something that doesn't work the way i would like. 

I have some 24V AC coil relays that work great down to around 15-16 VAC, they're yours for free for the cost of shipping.  If you want them, drop me an email to my profile address.  They're not really small, so under the table would be a good location.  They're overkill for this application, but the price is right.

My mistake. Single pole relays are all you need.   

Check out Azatrax.com.  I've got six of their MRAPR DPDT relays on my layout controlling crossings and allowing for two trains on a single track.   They work like champs.  Their website has a lot great "how to's" that were very helpful with wiring.