Okay you guys,
I have a question for you all, I want to have continous runs on my layout, and I'm thinking of having a dunkunder, what are the steps on building a duckunder bridge out of lumber. (it's to be in Nscale) do anybody have any pic's to post of there duckunders?? I would love to see what you have. Thanks
Take care
Trainsrme1
Let's see....first rule...don't have a duck-under.
If you are going to have one anyway, make it a lift-out or swing up/down/sideways so that you don't always have to duck under it.
If you are going to have a permanent, non-removable duckunder, build it where your tracks are at their highest elevation relative to the floor. The less you have to bend over, the fewer problems you are likely to have of the scraped back, banged forehead, or much, much worse, the dislodge and now misaligned tracks caused by duckunder damage.
So, I now confess to having two on my layout. One is the main entrance which is as wide as the entire bench. I am relatively short, but I still have some "thunks" and "ouch" es from time to time with the clearance of 44". The other runs diagonally across my central operating pit, but it is a swing down that is hinged at one end and held in place by two barrel locks at the other.
So, will yours be permanently fixed in place or hinged/lift-out?
Duckunders are bad enough, but I would agree w/ Selector on a removalable or swing away of sorts.
To make this vunerable spot a bridge is a recepie for a disaster. My back, shoulders and head have whacked the benchwork more times than I want to recall. Any bridge to span even the smallest access in N scale would be rather long and very unrealistic anyway. A simple sceniced swingaway,or liftout/ liftup would be a better choice in my opinion.
Modeling B&O- Chessie Bob K. www.ssmrc.org
That's my simple lift out bridge:
And this was the bridge in 2003:
Wolfgang
Pueblo & Salt Lake RR
Come to us http://www.westportterminal.de my videos my blog
~G4
19 Years old, modeling the Cowlitz, Chehalis, and Cascade Railroad of Western Washington in 1927 in 6X6 feet.
Please! Don't anyone bring up that old trite "Duck Under Here" gag!
From the far, far reaches of the wild, wild west I am: rtpoteet
To where would be bring it up if we brung it up?
selector To where would be bring it up if we brung it up?
Maybe I should have ask for forum members to post pictures of their "Duck Under Here"!
Serious questions here, relevant to this thread. I have HO 2 tracks spanning the room entry that I'm not thrilled about, but at this time are necessary. They are at 50" and 54" from the carpet, so I consider them nod-unders. I am still considering improvments here, but haven't executed yet due to priorities and lack of confidence in my skill.
Regarding Liftouts: Don't all liftouts require short gap spanning track to be installed? And if so, do people really lift these things out, or just duck under them whenever you want to operate? Do you really lift your bridge out, or is it a duck-under 90% of the time?
Regarding swing and drop down / lift up bridges: I have yet to see how to maintain the tight horizontal and vertical track tolerances required, given wood construction and (most people) using household hinges and latches. Granted, I haven't done it myself yet and am relying on experience with household projects that tell me that wood expands and contracts, and household latches have slop that would cause derailments.
What am I missing? Inquiring minds want to know...
I insert my bridge only if I have an op session or I want to run trains. Even if I run a local I don't need the bridge. Here're more pictures.
onebiglizardDon't all lift outs require short gap spanning track to be installed? And if so, do people really lift these things out, or just duck under them whenever you want to operate? Do you really lift your bridge out, or is it a duck-under 90% of the time?
No, you can cut your rails so that they meet with just 1/16" gap between those on the lif-out section and those coming to the ends of the bench on either side. What I think you may mean is that you would want a dead, electrically dead, section of track that must be activated with an SPDT on either side of the lift-out, but on the tracks leading to it. Each dead section would be about 18" long so that a creeping train whose throttle was left with enough speed steps (in DCC) couldn't approach the edge where the lift out is missing and tumble to the floor. I'm not sure what else you might be concerned about, but I think there is no compelling reason not to have anything more than a 1/16" gap at each end of the lift-out or swing bridge. I did it for my diagonal swing down and it works just marvey.
What you must do, if it will swing and be hinged, is be aware that the leading edge coming toward the bench will impact a square surface. So, the bench surface should be angled, and so should the swinging face of the bridge such that when they close with each other, the angle of each accommodates the closure. Then, use locks of some kind. I used brass barrel locks costing about #2.00 each.
onebiglizardI have yet to see how to maintain the tight horizontal and vertical track tolerances required, given wood construction and (most people) using household hinges and latches. Granted, I haven't done it myself yet and am relying on experience with household projects that tell me that wood expands and contracts, and household latches have slop that would cause derailments.
You are largely correct. Over time there will be some creep, and you will have to shave or shim a wee bit. Mostly, though, the secret is maintaining the ambient humidity around the layout in a narrow range, say between 30-60%. Much outside of that range will invite the need to make heavier adjustments.
I have a duck under on my layout which could be turned into a drop down/lift up if I decide to. Had a drop down on a layout years ago and found that 90 percent of the time I just left it up. My benchwork is 48" high so I don't mind the current duck under. Heck, some days it the only exercise my old bones get.
Dave
'there's something happening here, what it is ain't exactly clear' Modeling the Hard Knox Valley Railroad in HO scale http://photos.hardknoxvalley.com/
Since I needed a swing door I copied the design from a recent MRR article. Like your concerns my main concern was the adjustments to keep both horizontal and vertical aligned. So here are 2 photos of how I did it. Nothing fancy to be sure. But make sure the door is well designed, solid and use good hinges. Once the wood dried out (pine) I haven't had to make any adjustments. The 90 degree bracket was easy. I bent a piece of metal and tapped 2 machine screw holes. I soldered the round metal washers to the screws for easy hand turning. For the vertical, I just have a 3" wood screw that I can back out or sink as needed.
Tom
Thanks for the info, Yes I do mean a hinge (or) swing as my bridge across my door way. Send me more info if ya got them. Thanks