This is going to be rather picture heavy so bear with me. This is going to be the full build of a drop down entry I made for my around the room layout. The room is 10X14 and it is 33" wide(I'm little bit tall). The drop down is 33 1/2" X 10 1/2", wide enough for 2 HO tracks and a two lane road. First I cut a piece of 3/4" plywood to size plus a little bit for saw blade thickness because I wanted no flex at all in this bridge. (I know overkill) then cut off about 2 1/2" at a slight angle, about 10 deg, mounted it to the end of the table with angle brackets. Making it flush with the top of the table. I didn't use any foam on this because I just didn't think about it and making the angle cut is easier in wood rather than foam I think. Next I made a simple 2X2 frame on the under side and used flat hinges for mounting. Clamped the angled end in place and mounted to the other table making sure it was flush. Cut and mounted short 2X2s for the angled end and mounted some loops for slide locks. Now it was a little bit uneven after adjusting the slide locks as best I could but I just took a sander and made it flush. To be continued in next post David.
On with the drop down build. Then I mounted the roadbed in place in one piece over the cut then took a razor and followed the angle cutting the roadbed. I laid my rail in place and cut it with about a 10 deg angle with my Dremel. I brought the ends as close together as possible and fitted the hinged end of the track in the same manner without the angle. Now for the wiring. I am using simple touch contacts that is all. The metal is springy and have only had them loose contact once since I installed them. A slight bend to tighten up the contact and fixed. Wire loops with screws and washers on the ends and the metal strips on the other. The two outside wires (red and green) are the main buss wires to the drop down, the two inside are going back out to the 18" safety zone for both main tracks and a siding I have over there for that side. The main buss wires lead to a terminal block under the drop down. To the right is the drop end, feeder wires going left to 18" safety zone for the hinged side. The outbound main buss wires lead to another terminal block with feeders going to both main lines and a siding on the drop end side of the bridge. Wiring it this way if the bridge is in the down position all power is cut to the mainlines for 18" on both sides of the opening creating a safety zone so no trains can fall into the abyss heading for the floor. I have main buss wires on the other three sides of the layout feeding the rest of the track. Here is one of the rough draft drawings of my layout. I have been running this set up for about six months now and have had no derailments at the bridge joints. Just take the time to make the joints as close and lined up as possible and it should work out well for anyone. David
One thing I forgot to add in the build post. When you get the bridge cut and in place you will need to tweak it just to make sure that it falls away clean and does not hang up on anything. On mine it was just some sanding of the 2X2 ends and slight bending of the slide lock loops that touched when it was first put in place. David
Mucho late to this. Just fell upon it. Very solid lookin' job. Didn't read all but I hope it causes trains to stop well before it when it's down. I'm sure it does...M
