# Lift bridge / suspended bridge



## Tdreabe (May 3, 2020)

In order to still fit my truck in the garage, and have a 4 foot radius oval in the back, I needed to make the straight section away from the wall lift high enough for the hood to pass underneath.

The oval with the 13 foot clear span was completed back in the beginning of September.
First bridge crossing

Through the winter I worked on both "cars" that would follow the towers at either end of the bridge and one tower. My original hope was to build this as prototypical as possible, with a motor mounted on the span to lift the bridge. But as April showers are here, and potential hail in Central Wisconsin, I needed to just mount the lift points on the ceiling. 

For the first time since September, the bridge has been lifted.








The one tower, I still haven't connected the "car" to the bridge.








The north end wich has no tower.

I could have done single cables without pulleys on the bridge span, but my wife said the rotating wheel would add to the motion. I added a pulley in the lift rigging to counter them and maintain 1:1 on the cable.









The winch I used is a worm gear with 40:1 ratio. It is very easy to move, but takes some turning. I will be getting the necessary bits so I can operate it with a drill.

I have made alignment pin/feet for the span that I will need to install, dropping the tower by about an inch.

I soldered tabs to the ends of my rail hoping that I could anchor the track in such a way that when the pins center the bridge, I don't need rail joiners, but I think I want to find something like the splitjaw bridge joiners.

As of yet, the anchored rail without joiners is untested, but I am nervous to since a derailment is a 36 inch fall to concrete.

Either way, I have lifted the bridge and the garage is available to all of my vehicles again.

Tyler


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## fsts2k (Jan 13, 2009)

Super cool! Thank you for sharing


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## Pete Thornton (Jan 2, 2008)

Very neat. Quite similar to a boat lift. I always suggest looking at boat lifts when something like this comes up. You can proably find a small motor that will drive the worm to lift it from the same source.



Tdreabe said:


> the anchored rail without joiners is untested, but I am nervous to since a derailment is a 36 inch fall to concrete.


Two comments to that. First, the prototype guys put a side rail on the bridges just in case, plus a pair of guard rails down the middle to stop wheels heading too far over the side. And secondly, if the bridge rails extend 1/2" over the abutments at each side, you can put alignment pins/slots for the rails to drop in to and thus keep them where they should be for running - like the split jaws only cheaper!


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## Tdreabe (May 3, 2020)

I was able to make a Video of the bridge going up and down. Note that it still isn't complete.

After lifting it a few times I dismounted the tower and started working on the alignment pins and track security.

These pictures pretty much speak for themselves.


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## Pete Thornton (Jan 2, 2008)

Looks great!



Tdreabe said:


> and started working on the alignment pins and track security.


I would definitely suggest a slight file application to the inside of the rail ends so they don't have sharp corners. And if you extend the rails on the bridge 1/2" they can drop in to pegged slots and be perfectly aligned every time.
Some aluminum L angle at the sides might save your trains from an expensive fall to the floor.


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## Tdreabe (May 3, 2020)

Pete Thornton said:


> Looks great!
> 
> 
> I would definitely suggest a slight file application to the inside of the rail ends so they don't have sharp corners. And if you extend the rails on the bridge 1/2" they can drop in to pegged slots and be perfectly aligned every time.
> Some aluminum L angle at the sides might save your trains from an expensive fall to the floor.


Pete,
I have since become the happy owner of some split jaw bridge clamps (from the new owner) to take care of alignment of rails. The solder job I had was a learning experience and had much to be desired. Nailing the rail down like I had presented other challenges of equal rail spacing, level transitions, and rail twist if the base lumber wasn't perfect. The split jaws will also allow some movement if the bridge pins develop some wear. 

I will be doing some filing once the whole thing is laid out and a test car has been rolled through by hand.

As to the extra rails that are in the middle as is prototypical, what is the spacing? and since the price of rail has gone up considerably since my last purchase, what have other people used instead of another 26ft of brass 332 rail? .25 aluminum angle from the hardware store?

The outside aluminum railings will be a future addition I have to figure out. 
Reason 1: I don't want to create more bashed/cut Toddler foreheads than I already have with this bridge. They are learning to duck under things more effectively though. School of knocks is still a strong teacher. (I'm one of the believers in the fact that there are too many "Safety signs" that cover common sense.)
Reason 2: That is one of the coolest views afforded from that height on my current railroad. No step stool needed, steam puffs out, lone train with no background, view it from any angle. Get the Toddlers addicted to toy trains!!!
I'm thinking that any railing will have to be an open view type. Just a rail supported every 8 inches or so. I have also thought of building an arched truss structure to make the Lift bridge look more real even though it isn't needed structurally.

I am learning that engineering on the fly, leads to re-engineering on the fly and design changes, rebuilding, and severe delays in project completion. Good thing I'm a hobbyist and not hired to do any real work. The engineering is where the fun lies for me. Running the trains is a must to keep the interest going, but engineering in new ways, design puzzles, thats my fun.


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## Pete Thornton (Jan 2, 2008)

Tdreabe said:


> what is the spacing? and since the price of rail has gone up considerably since my last purchase, what have other people used instead of another 26ft of brass 332 rail?


Spacing is like a check rail on the switch, only more relaxed. 1/4" gap from the running rail to the guard rail should do it. All you want to do is stop the wheel that drops off on the outside from going off the ties, by keeping the other wheel from going too far sideways. 
There is plastic rail available which will do the job. $3.25 for 5' (if you can buy individual pieces.)
ProRail Display



Tdreabe said:


> I'm thinking that any railing will have to be an open view type. Just a rail supported every 8 inches or so.


That would look great. Maybe some brazing wire attached via tall cotter pins or soldered to nails. 8 inches between uprights isn't very prototypical though that may not be your concern.


> I have also thought of building an arched truss structure to make the Lift bridge look more real


Sounds like a great idea. Hells Gate Bridge in plastic?


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## Tdreabe (May 3, 2020)

Pete Thornton said:


> There is plastic rail available which will do the job. $3.25 for 5' (if you can buy individual pieces.)
> ProRail Display
> 
> Sounds like a great idea. Hells Gate Bridge in plastic?


The link you provided is for 100 packs, but they have 10 packs of plastic rail that will do nicely. Thank you.

My original inspiration on my bridge was the Duluth Aerial lift bridge in Duluth MN, or a Bowstring truss bridge. but in looking up the Hells Gate Bridge I came across the Royal Albert Bridge. and I think I like that ellipse look for the movable span.


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