Wiring a 450 Signal Bridge

[Roadmaster]

Here's my $0.02  I have (2) 450 signal bridges signalling tracks at each end of a double crossover.  I agree with GUNRUNNERJOHN - relays are the way to go.    

I use two 24 V relays tripped by insulated rails on a constant 20 V circuit - one relay for each 450 bridge.  Two wires run from the normally closed contact and two wires run from the normally open contacts. Each wire feeds a red or green bulb.  No dim bulbs on my layout! 

 All my switch indicator and signal bridge bulbs are LEDs from christmas light strings.  They are all 1.8 V and are on a separate circuit fed by an old 12V AC transformer.  It steps 20V AC to 1.8V AC.  I went to that complexity because if I buy a string or two after the holidays, the bulbs are cheap and the sockets are provided with the lights.  Plus the wiring is salvageable for low voltage use.  I admit,  It has it's problems, but I have the time to trace the occasional short. 

[Texas Pete]

Page 74 Classic Toy Trains March 2008 article, "Wire a more reliable Lionel signal bridge."

I built this circuit and it works well.  I use it to operate some action accessories other than signals.

I believe the RatShack parts numbers no longer are valid, and with the current state of their business you'll probably have to buy from a real electronics supply house.

Pete

[rrswede]

Thank you for the response, Pete. I have not had time to work on the 450 since my last post, but have made a copy of your information in case I fail to get the current hookup working properly and want to try an alternative.

Swede

[lionelsoni]

Swede,

The fact that you see a dim green light suggests to me that part of the problem could be that the misbehaving signal's green lamp may be wired to the outside rails of the track corresponding to the signal that works properly and not to the outside rails of its own track.  It's possible that, because of voltage drop in the outside rails that the outside rails of the two tracks are a little different.  When the green lamp is connected to the outside rails of the same track that has the control rail, it should be completely off when it is shunted by the dead short circuit of the train wheels.

If this is part of the problem, another way to fix it is to connect the outside rails of the two tracks together locally.  In addition to eliminating any difference in the voltage drops, this has the advantage of reducing the voltage drop generally between the train and the transformer by paralleling the return side of the circuit.  I recommend it wherever tracks happen to be close together, for that reason.

[rrswede]

Thank you for the response, Bob. I am utilizing three 1033 transformers on the layout. Transformer 1 is the power source for track one and train one. Transformer 2 is the power source for track 2 and train 2. Transformer 3 is the power source for stand alone accessories located around track one and track two and also is the power source for additional accessories controlled by isolated tracks located at various locations around track one and track two, including the 450 signal bridge.Signal one is wired to track one and signal two is wired to track two.  Does the wiring I have used lend itself to the situation you described?

Thanks, Swede 

[lionelsoni]

The accessory transformer powering either signal (transformer 3) needs to have a common return with the transformer powering the track.  Since there two signals, one on each track, all three transformers have to have a common connection, that is, one side of each of transformers 1, 2, and 3, must connect to the outside rails of both tracks, and to the green lamps of both signals.

So, for example, if you are using terminals A and U of transformers 1 and 2 for track voltage and terminals A and C of transformer 3 as a fixed 16-volt accessory voltage, terminals A of all three transformers and both green lamps would connect to the outside rails of both tracks.  Both red lamps would connect to terminal C of transformer 3, and the common of each of the two signals would connect the control rail of the track that it is associated with.

Is any of this different from what you have now?

[rrswede]

Thanks for your reply, Bob. The only difference is that the third transformer is currently hooked up using terminals A and U. Later this week, I will take another stab at the wiring and report what I come up with.

Swede

[lionelsoni]

A and U are of course just fine.

[rrswede]

It has taken more time than I thought it would but both lamps are now operating as intended. Just don't ask me to explain what I did to eliminate the dim lamp issue. I essentially disconnected and reconnected the wiring for all accessories that operated in conjunction with an isolated track, cleaned the track, made sure all lock ons were making good contact with the track, and the problem disappeared.

Thanks to all who offered assistance. Now off to the next issue.

Swede