Wiring Lionel Bascule Bridge

Yes,but I would use relays and maybe a timer instead along with an insulated outside rail. The train would have to stop and some sensor would have to hold it from starting until the bridge is down (reed switch or micro switch. As I remember some bridges kill power to the track block when up so it is already built in). The insulated rail method would be bi directional. Would have to see a terminal wiring diagram for the bridge. So really all you have to do is put the bridge down when the bridge block is occupied and have the default position up when the block is not occupied. You could add a soft start system with additional relays so the train does not start at full voltage. I believe for prototypical operation the boat would have priority over the train.

Dale H

Since this a somewhat rare piece you really don't want change too much of the wiring.

When you press the button you send power to the motor.  Once it starts a cam on the motor shaft closes the motor circuit and opens the track power.  The motor wil continue to run raising the bridge all the way up and back down until the cam opens the motor circuit and closes the track circuit.  You need to interrupt the motor circuit when the bridge is up.

I thought this up on my way home from work so, I haven't tried.  Fit a mercury switch on the moving bridge structure.  Run the 2 wires down to the base. The motor hot lead is the #4 post.  There are 2 wires on this lug: the motor lead and the beacon light.  Disconnect the motor lead.  Connect one of the switch leads to the #4 lug and the other to the now loose motor lead.

In theory, at least, when you push the button the bridge will go up as long as the mercury switch is closed and stop at the top when it opens.  Pushing the button will apply power to the motor, the mercury switch will close and continue until the cam opens the circuit.

Probably easier to write than do but this will preserve your bridge and still give you what you want.  Pushing the button could be replaced with a relay of some sort.

Good luck.

Dan

Dan

Do you mean the bridge can not be stopped in the up position? Is this the old version or the remake?

Dale H

The original 313, Dale.

You push the button long enough for the cam to engage the fingers of the switch then you can let go of the button.  The bridge will go all the way up and then down stopping when the cam finally allows the fingers to open.  You have to find a way to disconnect the motor essentially half way through the cycle.

I do not know about the new version.

Dan

Thanks Dan

In that case the easiest way I think would be to hook it to a timer set for half the cycle time , shutting off the power when the bridge is up, that should leave it in the up position. Then when power is restored the bridge would go down.

You could actually use a repeat cycle timer arrangement where the bridge would automatically go up and down by itself say 2 minutes up and 4 minutes down and repeat. An approaching train would automatically stop on the block as it approaches.

A second relay could prevent the bridge from opening (using the insulated outside rail method) by disabling the timer circuit if the train is already on the block when it is time to open. When the train passes the timer would resume.

This arrangement would be more realistic than the original proposed operation wanted by the initial post,I think,since it would not always be up when the train approaches. However the original proposed operation could be automated in a similar fashion.

This is all off the top of my head as I do not have the bridge to test but I think it could be made to work with relays and timers.

Dale H

Dale,

That should work without having to change anything on the bridge.

Just connect the leads from both the #3 post and the #4 post to the output from the timer.  That way the motor will start whether or not the cam has closed the motor circuit.  This will also leave the ability to have the bridge control power to the track.

As you point out, if you use a timer it is imperative that you have something to prevent the bridge from activating while there is a train in the block otherwise, you will have lots of equipment on your RIP track and damage to the bridge.

Dan

Just to answer the initial post question,where the bridge is up as the train approaches,then goes down and the train crosses,then goes up after the train leaves. This would require 2 dpdt relays and an interval timer and a few minor parts. An insulated outside rail would have to be made on the bridge approaches. The cost for parts would be about $30.

The repeat cycle timer method would require 3 timers and 4 relays and cost about $60 to make up. In this case the bridge would go up and down by itself,independent of where the train is but not rise out if the train is already on it.

Either method could be done without altering the bridge significantly as Dan describes.

Dale H