Lighting a signal bridge

[Mchavez215]

Thanks, Bob.  The bridge came unwired (a Bachman Plastictville model), just colored plastic lenses for the "lights" - so I "electrified" it.  This Radio Shack switch, and your description are exactly what I was looking for!

[lionelsoni]

Can you tell us the maker and model number, or describe how the bridge is wired?

If all the lamps share a common return, possibly through the frame of the bridge, all you need is a single-pole-double-throw (SPDT) switch like this one:

http://www.radioshack.com/product/index.jsp?productId=2062531

or practically any other SPDT that Radio Shack sells with at least a 1 ampere rating, or half of a DPDT if one of them looks nicer to you.

Wire the red from one side of the bridge and the green from the other to one outer terminal of the SPDT switch.  Wire the red from the other side and the green from the first side to the other outer terminal.  Then connect the center terminal of the switch and the common return of the bridge to the two transformer terminals that you want to use.

[Mchavez215]

Hi- I am attempting to light two signal bridges which each have a pair of fixtures with 1 red, 1 green and 2 amber lights (8 lights per bridge).  I won't try to control these with trains (a 027 layout) but with switches.  The amber lights will stay on or off via a switch - that is the easy part.  What I would like to do is wire the reds & greens "opposite" of each other:  when the red on one side of the bridge is lit, the green on the other side is also lit.  Move a switch from one side to the other and the alernate red/green light up.  Hope that makes sense.  I need a diagram and a switch number.  I've looked at Atlas' "Twin #210" but don't know if that is what I want.  Thanks!