Wiring track and block signs for two cab operations question.

[Texas Zepher]

in the past I used DPDT (one for signaling and one for track power). 

On DPDT each for signaling and track, or one side of the DPDT (a SPDT) for each?

[BigG]

 83' x ~20' sounds like a really large layout or club. Make no apologies for going DC, as a friend says "I want something I can fix". In my case I couldn't justify the cost of decoders at the time.   Thinking about your signals, it might be more prototypical to have a "no-green-no-go" indicator. That way there's no ambiguity for the locodriver.

    Have fun...George

[XMarine]

Not panel signals, block signals by the track.  This is because the layout will be 83' long and 20' wide at points.  There will be several control panels for local cab operations and a single main line cab (radio controlled) so that the engineer can follow the main line train around the layout.

 

Side note:  Due to the large number of pre-80's locomotives that would be very expensive to convert, the layout is old fashioned DC power.

[XMarine]

Just started the wiring of a totally new layout.  But normally in the past I used DPDT (one for signaling and one for track power).  If the cab is not on then no need for the signal to be lighted since no trains will be running.

[Texas Zepher]

I figured on the block signals being powered by the cab that is controlling the track.

You realize of course that that means the indicator lamp will only be on when the cab is turned on and supplying power to the track.

What switch type are you using for your block control now?   Is it a SPDT with one wire to the track or are you using DPDT with two wires to the track?

As someone else mentioned you could use a simple SPST switch and a relay with the 3PDT contacts. 

[BigG]

  Hi, using a dpdt switch is the cheapest way to go.  

a) Connect the 2 power supplies' negative outputs together, and wire that connection to 1 rail. This creates a common-rail system. Then connect the other (+) wires from the supplies to the Normally-Open sides of 1/2 of the switch, 1 wire to each. Connect the centre contact of that 1/2 of the switch to the other rail, and you now have a switchable block between the 2 supplies. I recommend you gap both rails at each end of the block.

b) Now for the light.. Use the AC output of the 'local' power supply and a suitable dropping series-resistor to limit the current to what your LED will handle, and wire 1 wire to the other 1/2 of that DPDT switch, using the centre contact. Wire the LED from the N/O contact that will allow the LED to light when the 'local' (not 'Mainline') power supply is actively connected to the track. Use a red LED to signal that the Main is interrupted. When the 'Main' pwr supply is active, the LED will be off. If you want 2 Leds, 1 for each supply, add a 2nd LED and wire it to the opposing N/O contact. Make that one green, and it'll light when the 'Main' supply is active.

 You could use the other supply if having a dark indicator (only 1 LED present) for mainline 'OK' bothers you. I hesitate to recommend you couple the 2 supplies in common more than once. I have some that do not separate the AC and DC outputs completely. A cheap Battery eliminator would work ok in place of the track-supply's AC output; the advantage being the LEDs would always be ready for power, even if the track supply isn't turned on.

     Have fun....   George  

[BlueHillsCPR]

I am assuming you are meaning indicator lights on your panel not block signals by the tracks.

I have seen just recentley 4PDT switches on Ebay.  Otherwise couldn't you use snap relays?

Maybe I am misunderstanding your intent here? 

Edit: Or like Larak said 

[larak]

1) Use a multipole relay

2) Keep one rail common to both packs and only switch the other. On the second pole of your switch, switch power to the bipolar LED.

These are the two simple solutions. There are other I suspect.

Karl 

[aav]

      XMarine,   When you say "block signal" are you talking about the signals by your track?  If so, those are usually used to govern train movement , block occupancy, position of switches, etc.  Or are you talking about some type of lights on your control panel to simply indicate witch throttle has that section of track?

[XMarine]

I am building my dream layout finally.  There is a section of track that I will have switchable between a local cab and the main line cab.  I want block signals that will signal which cab has control (i.e. shows red to main line feeder when track is on local cab and shows green when on main line cab).  I figured that meant on the control panel switch incoming of two track wires  and two signal wires (common and light on) from each cab with outgoing of two track wires and three signal wires (common, red light, and green light).  I can not find any 4 or 6 pole, double throw switches.  I figured on the block signals being powered by the cab that is controlling the track.  How can I wire the block signals to show which cab is in control of the track and only have to throw one control panel switch?