[Dave F]

As spring slowly dawns on Utah I am preparing to start the spring expansion of the LP&W. I'll be employing the raised benchwork style of construction made famous by Richard Smith. On the north turnaround loop I have a delimma. The trackwork will be elevated about 3 feet off the ground and will encircle the planting bed where we grow our vegetable garden. Obviously I want/need access to the garden. I was considering putting in a lift bridge on one side so the Wife or I can just lift the bridge and step into the garden.

Does anyone have any experience with such a bridge? Any designs available? Tips or techniques that I need or prior experience I can benefit from?

Please, share what you know. Constructin begins shortly.
and I NEED my tomatoes and peppers!!!

 

[Guest]

for a similar situation (access to a door) i am going to make a hove-truss bridge of three foot.
the two mainbeams below the sleepers will be four foot long.
two inch from the left end i will screw on a hinge from below, to open the bridge like a trapdoor.

 

[Jerry Barnes]

HIllman had some rail clamps that let you lift it out, not sure you can find any now though, since they closed down. Jerry

 

[Richard Smith]

One guy I used to know in HO used brass cabinet door catches, two on each end, to secure a lift out section (doesn't have to be an actual bridge if it's not too heavy). The catches automatically lined up the track when the lift out was snapped into place. He even ran track power through them. I don't know what weather issues you'd have with them outdoors but they're pretty cheap and can be replaced easily and cheaply if needed. Track power could be routed through plug in wires if that's an issue or if using battery power there'd be no problem anyway.

I would prefer a lift out as opposed to a hinged type because of the vagaries of the wind blowing it down from the open position and causing damage. You'd have to assess the wind factor there for yourself. Of course you might be able to fabricate a suitable safeguard.

 

[Dave F]

Korm, excellent, thanks a bunch, that gives me a great start on a lift design.

Richard, I was thinking along the line of a full removable section as well for the reasons you indicated. BUT... with the wife and kids entering the garden, I can also see an advantage on keeping one end connected (hinged) and one end with some form of registration so the track aligns correctly each time as well.

Ohh decisions decisions.. I'll get it worked out..

Love the ideas/suggestions so far.. Keep 'em coming.

 

[Guest]

i will adapt my bridge on the "loose" side with Richard's idea, cabinet door catches.

if wind might be preoccupating, just lay a hook, of the kind to fasten open windows beside your track (hidden by a boardfence or something), that you can hook in the bridge, when open.

 

[Dougald]

Dave
The IPP&W (the host railroad for the OVGRS see www.ovgrs.org ) has two hinged bridges to allow the type of access you describe.
Both of these are made of metal - the latest one aluminum channel to keep it light and strong. Registering the tracks is done by the alignment of the bottom of the channel while holding the bridge in the hinged up position is accomplished by a metal strap with a hole in it that fits over an indexing pin on the raised benchwork.
Here is a pic

The metal strap can be seen (barely) hanging down at the left side of the photo - we have since put a screw into the channel and rest the strap on the screw.
This particular bridge has been installed for 3 seasons and has always operated perfectly.
Regards ... Doug

 

[Guest]

Dougald,

how do the tracks meet?
are they cut vertically or with an inclination to fit upon each other?

 

[Richard Smith]

Just one safety feature for you track power guys....

Make insulated blocks (track sections) on either side of the bridge or lift out and supply power from it (bridge, etc.). That way the power will be cut a few feet before the gap whenever the lift out is removed or the gate opened. Can avoid a costly mishap if someone opens it while a train is running. Us battery guys will just have to watch where we're going.

 

[Dougald]

The tracks just align with a small gap ... as Richard pointed to, we are battery or live steam only so no concern about electrical continuity. The channel is held in place at one end by the hinges and at the other, the sides of teh channel slip over a block of wood tightly to hold it in place.

It is a simple but very strong and effective means of bridging a gap that must be opened often. The bridge is normally down and then lifted for access through the gate - there has never been a loco run through onto the ground.

Regards ... Doug

 

[jimtyp]

Korm, I think you could solder a wire from bridge to layout on the hinged side, but on the side you lift up that would be quite a long wire and probably not desired at all For the lift side I'd use what Jerry or Richard said.

 

[Dave F]

Nice Doug. I hadn't considered using metal channel. That is an interesting idea I may need to persue further. Looks to be a good strong span..

 

[nkelsey]

Hillman also had a hinge that worked with their bridge clamps if you can find them. I have a lift out section using hillman bridge clamps for access to my wife's veggie garden and it works fine. As batteries do not care about connectivity on the track, i lay the section taken out on the track as a block.

 

[Guest]

thought a bit about it.

Richards idea with the cabinetclamps on the not hinged side unify two things. aligning the trackpieces and making electrical contact.
at the hinged side short ends of wire seem the best option.
for safety i think i found the simplest solution:
each of the two circuits gets one rail connected to the powerpack left of the bridge, and the other on the right side of the bridge.

so by simply lifting the bridge, both circuits are interrupted.

 

[Torby]

The way you've drawn it, the rails will be in the way when you lift it. You need the hinge above the rails so they separate as it pivots up.

 

[Rod Fearnley]

I just bought a pair of the bridge rail clamps here at the NGRC, I assumed they were from Hillman's. They also had the hinge bracket/system available. I'm going to browse around down there again in a little while I'll get contact details for you, and publish them here.
Rod

 

[Guest]

the rails will be in the way when you lift it. You need the hinge above the rails so they separate as it pivots up.

i don't think so.
i know, it is nearly invisible on the first plan, but the idea is, to cut the rails not vertically, but inclined. so, that at closing the bridges rails on the hinged side touch from below against their counterparts.
(while the rails on the opening side close from above upon the ongoing rails.)

 

[jimtyp]

Posted By kormsen on 05/02/2008 12:11 PM


it is nearly invisible on the first plan, but the idea is, to cut the rails not vertically, but inclined. so, that at closing the bridges rails on the hinged side touch from below against their counterparts.








Very clever!

 

[Torby]

OIC!
They're behind the hinge so the rail ends would move down.

I didn't have anything to hold the ends of the rail, but relied on accurately positioning the bridge when you set it down. It nearly worked. You had to remember to shove the bridge to the north when you put it back down 'cause the locators were about 2mm too wide.

 

[jimtyp]

Korm, Once the rails come down and contact on the lift side of the bridge, how do you keep the rails lined up? That is, the rails are cut so the lift side can go up and down (clever), but will you need something to keep the rails aligned when they come down?