3 line swing bridge installed

Nice,  I took the easy way by using the Mianne lift bridge to raise my 3 levels for my 8 loops.  I prefer your solution because I still have a slight duck under.

Nice work,  I will keep your plan in mind as my new layout will swing out for access. Thanks for sharing. Nick T. 

Good solid design.  Don't forget to close it. I did that once , but caught mistake beforehand. 

Don't forget to put in a power interlock on the approach tracks to the bridge.  If it's open, kill power 3 feet in each direction.  This will prevent headers to the floor.

Fred

Nice work Kirk! I built myself a lift bridge with an electrical actuator to lift it almost to a 90 degree to be able to gain access to my train room!

There's a deadbolt behind the door that should hold solid.  I'm going to rig it to a microswitch and buzzer system powered by layout power.  If the gate's not closed and bolted then it'll make racket.  With 3 separate power districts/loops going over that just seems a major hastle to rig something up to turn off power.  But I'll evaluate that when I get to electric. 

The other option is some sort of physical barrier that pops up, triggered by the door being opened, I have seen where they have a non metal rod pop up between the middle and one of the outer rails next to the opening, triggered by the door being opened, then when you close the door it forces the rods down......not sure that is easier than killing electrical power to 3 foot blocks on either side of the bridge, both require some significant work. The manual method (which is fraught since it relies on thinking) is to put a heavy object on the rails while the door is open, so no one can run a train off the opening, but that won't help the situation if you open the bridge and forget you have trains running and they come before you are able to block it......

Here is an easy way I set up a relay to de-power multiple tracks if my bridge was not in place:

The only things I needed to by was the DPDT relay and the transformer for it.  I insulated the tracks on either side of the sections against the bridge.  Then I wired the Common to all sections as needed.  The Hot from the Transformer went to the input side of the Relay (C1/C2).  The hot was then sent to the three different sections of each track (leading, bridge, lagging) from the output side of the relay (A1/A2).  Then I used a simple circuit from the Relay transformer that went to the locks on the bridge.  If either lock is disabled, the relay will send the hot to the B1/B2 poles which were not wired in.  Once the Locks are engaged, the relay sends the Hot to the A1/A2 poles which then go to the track.

On the picture above, it only shows 2 sets of relays.  The actual one I use powers 4 independent tracks (like the one below), so it has 2 additional sets of inputs/outputs that I don't show for my upper level.  All are in one small package that looks like this:

I found the one above on Amazon via this link.  This one would let you run your lock through the upper connection (just under the relay), and then your input/output for your three mains.  You could use the 4th set for a light or buzzer to activate when the locks are disabled.  It is 12 V input to power the relay, and is rated for 10 AMPs at 240V, so it is more than strong enough for the track power (18V, 10 Amp).

I run 2 rail. The simplest way of adding a safety to prevent trains running off the opening when the bridge  is open is to cut the ground rail before and after the bridge. Leave enough space th stop the train before it reaches the end. Then just add a micro switch either momentary on, lever or button. Wire both sides of the bridge to one side. The wire would go over the door frame to the switch. It is all mechanical with no relays or intricate wiring. If you run 3 rail use switches on both sides of the bridge on both ground rails.

Since I'd be running that track power through a relay anyway no need for the 4PDT relay (which does look neat).  ebay has 10 of these SPST microswitches for $1.92 and I could use one for each track control wire (not higher current power feed) and a spare for a buzzer and have 6 for spares/other projects.  No worry about the current capacity or wire length for just a relay control wire I don't think.  Lots of options indeed.

Here is what I did, simple and works great, I just power the bridge and put contacts on both ends. This powers the adjoining tracks when the bridge is down, and  turns them off when it up. Someone told me KISS so I did! LOL

Kirk,

I like your design. Visually, it's the best I've seen and the design looks adaptable for any table top width.  Would you share with us the dimensions of the door and the angle of the cut on the deck?    

Earl 

You think I had a design?  Door length width was dictated in my layout design software... 36".  Height is around 33" to allow for 2" wheel at unhinged part of door (very important!), 3/4" plywood and shims to get to 36" total height.  I made sure the jamb where it was hinged was as stable as possible and perfectly vertical and attached to floor (screws going through floor plate to go through carpet and impinge on concrete subfloor).  Once door was attached the second jamb, where it locks, was cut to fit.  The top angle was determined by a putting tape measure from the hinge point (front left) to the opposite corner (back right) and drawing a curve towards the front outer edge keeping the tape measure the same distance (basically pivoting around the hinge)... that back corner is the one to be worried about the most.  Then you draw line from back right corner to the front with a straight edgemaking sure to avoid the curve completely.  My angle was about 20 degrees.  

It's a darn sturdy 2"x4" frame where I can add balusters or maybe a RR crossing sign or something.  I need something to prevent kids from crawling over and throwing it out of true.