removable bridge/duckunder

[Anonymous]

Hi all,
I searched for these but couldn't find anything so am asking for any help or suggestions that are out there. i have made a change to my track plan that will allow me to get more mainline but it will require that i build a duckunder or removable bridge. My question is how do i get the track to line up every time i install the bridge and to keep it aligned while running trains. I plan on having my track around 46 inches above the floor . I was thinking something like dowels or so on. Any advice or suggestions let me know. Thanks in advance. P.S. The garage is now cleaned up and ready to paint which equals 1 step closer to benchwork building time.

[Big_Boy_4005]

There are a lot of methods for dealing with this, including hinges, slide latches, and V notches. Dowels would probably work, but they may not be the most elegant solution.

We have had a number of topics discussing this idea in the past, but the searching is a bit tricky. Try the advanced search, and don't forget to open up the dates beyond the last month.

[Anonymous]

I built a duckunder across a doorway, to extend my main line. I use 3/4" BC plywood for subroadbed, and Homasote for roadbed. The line is single track at the du, and makes a curve through from one wall at a right angle to another. To maintain rigidity, I bought 1/8" x 1" aluminum strip, and epoxied and screwed it to the curved sides of the du, with right angle brackets, mounted underneath the plywood subroadbed. I installed a piano hinge at both ends of the du, and installed the track. I then cut through the track, roadbed and subroadbed, centered over the joint of both hinges. I replaced the wood screws at one hinge on the wall side with threaded studs. When I want to raise or lower the du, I unscrew the nuts from the studs, and drop the du. The reverse procedure puts it ack in place. The piano hinges and aluminum strips keep things in alignment. I hardwired leads from one pair of stock rails to the bridge rails which form the du. The layout is in my basement, and the du has been in operation for many yeaers, with no problems. After a year of so of running, I cut the excess off the right angle brackets, and the aluminum strips look sort of like a truss bridge. You want to use small piano hinges with a number of scew holes in them. Make sure you intall them with the roll of the hinge down. The aluminum I got at Home depot. Good luck & enjoy.

[SteelMonsters]

http://www.trains.com/Content/Dynamic/Articles/000/000/001/431wikvc.asp


I guess that should help. Duckunders are the devil, you find that one out soon after building one.

[jwar]

Steelmonsters post is a great swing type. I could not side swing and built three lift up types and a drop in to span two doors for an around the room layout. The forth would have been a lift up, but the upper level track and the cieling prevented this.

Drop ins are easier to make and either doweling, pinning usually gives good performance. I may get flamed for this (but then I havent been flamed since the wife went to work) , but I hate a drop in, its slow to set in, take out and someone allways sets it where it dont belong. Seems im either heading for the coffee pot, phone, and of course the emergency ones (more rapid trips to another part of the house to get rid of the coffee) Theres nothing wrong with drop ins, just my preference.

The key to a good lift up or side swing are good hinges, not the garden varierity hardware type. Piano hinges have to be screwed from the side and one looses the structure of the plywood. Door hinges work great and are actualy cheaper and stronger, but have to be mounted under the lift up.

Perhaps a hinge as in the 2005 MR Great Railroads, Pg 92. It would hinge above the track rail, made by Amrock and is a flush mounted cabinet type. (Note the rails sticking up over the end)

I build a L shaped henge mount out of 1x4, inverting it and mount on the side frame of the layout with the inverted L facing the layout. Mount the widest door hinge I can find ($3.78) and mount it approx 4 inches from the end, under the drop down. This permits it to stay in place after lifting it, as it swings up and over center. A 2x4 cut at 45 degrees mounted inside the L really stiffens it. Very quick to use.

Wire the track from the hinge side. Perhaps a micro switch to kill power when its up, brings a different meaning to dead heading or perhaps wallet thinning.

For alignment I used 1/4 in round headed bolts these have a allen head set screw in the center of the bolt head. Inserting into threaded nut that has a flange for nailing (track nails) into the side of the lift up. Drill a clearence hole in the side of the lift up end. Most hardware stores have these in those little side out boxes in the speciality screw and fastener section. Adding a lock nut it is easialy adjustable to .001 of an inch side to side adjustment. The head of the bolt can be adjusted to anthing metal, one on each side. I use these for both vert and horz adjustment. Wood swells and things move. Also an old fashonded window sill fastener works great.

Which ever type you prefer, keep both sides on the same height level. If not you wont have to buy more uncouplers. You can also cut rerailers and mount them on the ends,1/2 on the layout, 1/2 on the drop in or lift up. With good alignment you wont need them.

well thats my 2 cents, go for it, with whatever you think is best. Take care.....John

[BR60103]

I made a drop-in, in two sections, with a 90 degree curve on it.
I wired it so that one rail picked up current from the shore at the left, passed it on to the shore at the right. The other rail passed current the other way. That gives me two dead sections when the section is removed.

[Anonymous]

Here you go guys and gals, I'm building a new layout that has a doorway to deal with and I started to build a dropin and then I thought this is nuts, it's to
much screwing around. I went to Fleet Farm and for 25 bucks bought one of
those little chairs with wheels that guys that fix cars use. From the bottom of
my benchwork to the floor is 46". I just plop my fat behind on the chair and
zoom right through the door and under the layout and as a added bonus the
chair has a tool holder under the seat (great for wiring under the layout as well)
By the way I'm 6'3" and have not beaned my mellon yet using my little chair. Hope this will give you something to think about[:)][:)][:)]

[eastcoast]

Duckunder Bridges ???
I have two of these things at a doorway. I am also 6' 4" and do
not "duck" so well.
I took the bridges and cut them so that they rest on top of a
1x4 at each end of the permanent layout. I cut the bridge ends
like a jigsaw, so there is only ONE way to fit it in. The track will
line up perfect every time. Leave enough rail space to slide the
joiner onto the rails to connect for continuity. For added strength,
a screw is recommended at some point.

[ndbprr]

I'm 6'5" and built a duckunder when I was in my 30's. Now that I am in my 50's it is long gone. Duckunders are good for ducks and that is it in my opinion. Now if it is possible to have a removable section it is one thing but I operate on a beautiful railroad that requires me to literally get on my hands and knees to get to the other side half a dozen times or more a session. Arthritis and wear and tear have made this an unenjoyable experience and I will not have one on my railroad. My only advice on anything of this type is that it be built to withstand an earthquake of at least a magnitude of 10.0. Most people will bump into the bottom on a regular basis. I would bolt either side to the floor and use 2x10 or bigger wood for every component. I have seen people raise them 4" off the floor.