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Scratchbuilding Towers for a Vertical Lift Bridge

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  • Member since
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Posted by hon30critter on Monday, April 29, 2019 4:58 PM

Hi Rich,

Interesting challenge with the pulleys.

I'm wondering if you could draw up a side view of the original pulley (you might have to use your imagination because you can't see much of it), and then make photocopies to glue to either side of the plastic pulleys that Rich suggested.

Just speculating.

Dave

I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!

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Posted by zstripe on Monday, April 29, 2019 4:05 PM

Rich,

I think I may have found a viable answer..........take a look at all these. They may just have the size You could use and it would not be too hard to drill holes into them, they are plastic. I have used similar ones before. It also looks like you get 10 pc's for the price...........I for one would surely try them and get them to work...........

https://www.amazon.com/slp/plastic-pulley/upeuzpqdpeyt67b

Take Care! Big Smile

Frank

 

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Posted by richhotrain on Monday, April 29, 2019 9:30 AM

Ed, I am going to have to paid you a finder's fee for all of the good work that you are doing on my behalf.

I do have resin casting materials, thanks to Mel who was instrumental in helping me with an alternative to Walthers Modulars when they were no longer available. My problem with resin castings, though, is that I have been totally unsuccessful with finding an adhesive for resin castings.

I have thought about using Tinker Toys. In fact, Shapeways has a sheave that looks a lot like a Tinker Toy. LOL.

Those wood spools look excellent. I am going to make a trip over to Hobby Lobby to check them out.

Thanks for all of your help, Ed. And don't stop looking. Remember that finder's fee. Laugh

Rich

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Posted by gmpullman on Monday, April 29, 2019 8:39 AM

richhotrain
Yep, I do like those a lot. The problem for me is price.

I feel your pain, there, Rich. I figured the casting route wouldn't be cheap, either, after all the silicone and resin, so these might balance out.

Come to think of it, old Tinker-Toy hubs... oh, wait, those are rare, vintage collectables, now. Maybe some of the craft stores would have wood wheels or craft doo-dads that you could drill and carve?

Still trying out ideas.

[edit] Hey, look at this, first try out!

https://tinyurl.com/y5gbb5lc

I Googled "wood craft wheels"

Buck a piece at Hobby Lobby (the 2" are 50¢ each):

https://www.hobbylobby.com/Crafts-Hobbies/Painting-Surfaces/Wood/Birch-Wood-Tread-Wheels-with-3-8%22-Hole---2-1-2%22/p/23024

You could cut out a styrene disk cap for the sides.

Cheers, Ed

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Posted by richhotrain on Monday, April 29, 2019 8:32 AM

gmpullman

Don't forget about these "Scene Master" gears. For all that trouble, these things would sure make a good starting place.

 Cog-Life-Like by Edmund, on Flickr

They measure 1.3795 OD. If you wrap them with grooved material you can get to your 1.900 (1-½" pipe OD).

Ed

Yep, I do like those a lot. The problem for me is price. I need 8 sheaves, so that would be four 2-packs at $7.00 a pack. But, to make this look right, I might neded eight 2-packs at $7.00 a pack, so I can bulk up the appearance of hefty sheaves.

This little project is already costing me more than if I had just purchased the CMR double track lift bridge like Frank did. Frank warned me that the sheaves for going to be an expensive add-on, and he was right. Super Angry

Rich

 

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Posted by gmpullman on Monday, April 29, 2019 6:46 AM

Don't forget about these "Scene Master" gears. For all that trouble, these things would sure make a good starting place.

 Cog-Life-Like by Edmund, on Flickr

They measure 1.3795 OD. If you wrap them with grooved material you can get to your 1.900 (1-½" pipe OD).

Ed

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Posted by richhotrain on Monday, April 29, 2019 6:39 AM

gmpullman
 
richhotrain
Here is a partially concealed view of the actual sheave. I would really like to find something that is solid, as opposed to open spoke, but that is proving difficult. 

Have you considered making a styrene master then a silicone mold and resin castings? You could add Archer rivets. Maybe even cast any other parts while you are making the mold?

I had hours into making parts for a Hulett ore unloader right about the time Walthers came along with theirs Hmm

Cheers, Ed 

Good question, Ed. Yes, I am considering a master from which I can do 8 resin castings.

I am also considering the use of 1 1/2" Schedule 40 PVC, thin wall water pipe, to cut eight 3/4" wide sections of 1 1/2" diameter pipe sections. I would then cover the ends of each section with styrene sheet cut to fit over the opening and add "ribs" of rivet plate to simulate the embedded spokes.

Rich

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Posted by gmpullman on Monday, April 29, 2019 6:27 AM

richhotrain
Here is a partially concealed view of the actual sheave. I would really like to find something that is solid, as opposed to open spoke, but that is proving difficult.

Have you considered making a styrene master then a silicone mold and resin castings? You could add Archer rivets. Maybe even cast any other parts while you are making the mold?

One of the gears I showed in this photo from March 30 looks like it would make a good starting place (the one that looks like a telephone dial?)

 cog_3 by Edmund, on Flickr

Slice some styrene tubing or wrap the circumference with strip styrene and you have the beginnings of your master.

I had hours into making parts for a Hulett ore unloader right about the time Walthers came along with theirs Hmm

Cheers, Ed

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Posted by richhotrain on Monday, April 29, 2019 5:47 AM

mbinsewi

Rich, I was on Shapeways earlier this am, read your last post, so I thought I'd look around.

I found these, they are 1.77", with 6 spokes.  

//www.shapeways.com/product/R4ZY5JNEW/45mm-sheaves?optionId=61536622&li=marketplace

Just thought I'd pass it back to you.

Mike 

Thanks for that link, Mike. That could work.  I am getting close to focusing on the exact sheave that I need to select.

Here is a partially concealed view of the actual sheave. I would really like to find something that is solid, as opposed to open spoke, but that is proving difficult.

Rich

sheave.jpg

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Posted by gmpullman on Sunday, April 28, 2019 5:15 PM

Perhaps take a second look at the Tichy offerings? 

https://www.tichytraingroup.com/Shop/tabid/91/p/8310-4-diameter-sheaves/Default.aspx

If they are ganged together the spokes won't look so "spindly". Actually the 1/2" diameter sheave is a little beefier than the larger ones but on the small side for your HO needs. Dave Tichy might be able to put together a quantity package for you. 

 

Good Luck, Ed

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Posted by mbinsewi on Sunday, April 28, 2019 10:33 AM

Rich, I was on Shapeways earlier this am, read your last post, so I thought I'd look around.

I found these, they are 1.77", with 6 spokes.  

//www.shapeways.com/product/R4ZY5JNEW/45mm-sheaves?optionId=61536622&li=marketplace

Just thought I'd pass it back to you.

Mike.

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Posted by richhotrain on Sunday, April 28, 2019 8:25 AM

zstripe
 
richhotrain
Frank, tell me more about those sheaves. Are they from the CMR bridge kit? Shapeways?  

Rich,

They are from the CMR kit. For some reason, they had a complete sheet of parts to make two more hoist platforms which are extra, once kit is finished. They are 7/8ths'' in dia. To make one sheave, it takes three piece's, two outer, one inner. 

Thanks for that info, Frank.

I continue to search for the most appropriately shaped and sized sheaves for the towers. There are 8 sheaves up there, 4 per tower.

On the actual PRR lift bridge, the sheaves were 15 feet in diameter, which converts to 2.07 inches in HO scale.  However, since my bridge and towers are scaled further down to 80% of the prototype in HO scale, the sheaves would be 1.65 inches in diameter. Right now, I am considering sheaves from Shapeways that are either 1.2 inches or 1.4 inches in diameter.

The actual sheaves on the PRR bridge have 8-spokes, just like those in your CMR kit. The Shapeways sheaves that I am considering only have 4 spokes.

Rich

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Posted by zstripe on Saturday, April 27, 2019 7:57 PM

richhotrain
Frank, tell me more about those sheaves. Are they from the CMR bridge kit? Shapeways? 

Rich,

They are from the CMR kit. For some reason, they had a complete sheet of parts to make two more hoist platforms which are extra, once kit is finished. They are 7/8ths'' in dia. To make one sheave, it takes three piece's, two outer, one inner. I also still have two 50ft. complete decks with piers, that I did not use.

Take Care! Big Smile

Frank

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Posted by richhotrain on Saturday, April 27, 2019 4:34 PM

Track fiddler

I fell out of the progress here with vacation and then back to work and all.  

The progression quality looks just as good as where I had left off.  Yes Still looking Great Rich, keep up the good work.

TF, as always, I appreciate your kind words of support.

Rich

 

 

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Posted by richhotrain on Saturday, April 27, 2019 4:33 PM

zstripe

Rich,

I would just like to also say, that you can use hardened brass rod from K&S in the appropiate diameter for the cables. It will be much easier to bend/cut than music wire, You may find that is better to use for You. It will also keep it shape and remain tawnt for the cables. It comes in various diameters in 12'' lengths and 36''. I made a mock-up using 3/64'' brass rod and used the sheave to make the bend on both sides to go over/in the sheave for the main span and over to the counterweight to the other sheave to give you an idea of how you can do it on the hoist platform. Do some measuring for the lengths/bends and use that for a master to make the others you will need so they are all the same:

Be Happy, in Your Work! Big Smile

Frank 

Frank, tell me more about those sheaves. Are they from the CMR bridge kit? Shapeways? 

I appreciate your work with the K&S brass rod to illustrate the point. Something for me to think seriously about.

Rich

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Posted by Track fiddler on Saturday, April 27, 2019 2:21 PM

I fell out of the progress here with vacation and then back to work and all.  

The progression quality looks just as good as where I had left off.  Yes Still looking Great Rich, keep up the good work.

TF

 

Frank I got to say your Bridge looks pretty sweet too.  Some good ideas shared.  I like the pulley idea.

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Posted by zstripe on Saturday, April 27, 2019 2:05 PM

Rich,

I would just like to also say, that you can use hardened brass rod from K&S in the appropiate diameter for the cables. It will be much easier to bend/cut than music wire, You may find that is better to use for You. It will also keep it shape and remain tawnt for the cables. It comes in various diameters in 12'' lengths and 36''. I made a mock-up using 3/64'' brass rod and used the sheave to make the bend on both sides to go over/in the sheave for the main span and over to the counterweight to the other sheave to give you an idea of how you can do it on the hoist platform. Do some measuring for the lengths/bends and use that for a master to make the others you will need so they are all the same:

Be Happy, in Your Work! Big Smile

Frank

 

 

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Posted by richhotrain on Saturday, April 27, 2019 8:58 AM

BroadwayLion

You is a model builder, where as I, on the other hand, am a fat furry LION with big furry paws, If it looks like a bridge, then it might be a bridge. 

ROARING! 

Maybe so, but to tell you the truth, him posts interesting photos of bridges and me ain't LION.

Rich

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Posted by BroadwayLion on Saturday, April 27, 2019 7:11 AM

You is a model builder, where as I, on the other hand, am a fat furry LION with big furry paws, If it looks like a bridge, then it might be a bridge.

 

ROARING!

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by richhotrain on Saturday, April 27, 2019 4:26 AM

zstripe

Without any doubt...use K&S music wire for the cable. 

Hmmm, I have given some thought to the cable, but I had not considered music wire.

I plan to follow the prototype somewhat closely, so I will need a system of 12 pulleys and 8 sheaves.

The sheaves will be placed on the top of the towers, one on each corner of each tower. The sheaves will control the movement of the cables between the bridge and the counterweights. I haven't decided yet on the number of cables.

The pulleys will be mounted on the bridge, four outside the bridge tender's shack in the center of the bridge, four on the top of the bridge near the ends of rhe bridge, and four on the ends of the bridge. The cables will be routed around this system of pulley and connect to the towers near the top and bottom. This pulley system, activated by the bridge tender inside the shack will activate the cables that initiate the lifting and lowering of the bridge.

Rich

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Posted by zstripe on Saturday, April 27, 2019 2:59 AM

Rich,

Without any doubt...use K&S music wire for the cable. Not a problem to keep tawnt and having all of them the same. Mine are close to 1/16th and they hold the counterweight in the air...nothing else holds the counterweight in place. Mine are plastic acrylic boxes. Yours as a suggestion.....a white pine block of wood, sanded to a texture of concrete. The music wire is more than enough to hold the wood. I would also invest some money into the  Xuron cutters #2193 they DO NOT distort the cylindrical shape like a side cutter will and cut like butter. Well worth the investment for Me, I use a lot of music wire for projects. A small size pair and large for cutting over a 1/8''. I air brushed My cable steel color from MM after lightly sanding the music wire and used Medium CA for bonding.

This pic was not touched up yet!

Take Care! Big Smile

Frank

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Posted by mbinsewi on Friday, April 26, 2019 2:37 PM

Have to go back and check out the pictures Ed posted again, and take another look at the tower foundations.

Mike.

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Posted by richhotrain on Friday, April 26, 2019 2:31 PM

I have added the tower decks, a system of welded girders that match the bridge girder deck. One advantage of having purchased three bridge kits is that I had plenty of extra parts after lengthening the bridge. I was able to use the extra bridge girders to build the two tower decks.

I am uncertain as to whether I should add the girder lacings and X-braces to the tower decks to match the girder lacings and X-braces on the bridge. Any thoughts on whether tower deck lacings and X-braces exist on the prototype? Or, are those lacings and X-braces only required on the bridge span over open water?

Rich

 

P1010866.jpg

P1010880.jpg

P1010879.jpg

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Posted by BroadwayLion on Friday, April 26, 2019 9:19 AM

The next crossing of the Gowanus Canal is at Carroll Street.

 

It is a slide bridge.

 

Isn't that ROARING

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by richhotrain on Thursday, April 25, 2019 5:30 PM

Thanks, Ed. 

Hey, go ahead and build a vertical lift bridge. Frank and I could use the company.

I have been considering both cable and sheaves. I haven't decided on anything yet, so I am open to suggestions.

Rich

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Posted by richhotrain on Thursday, April 25, 2019 5:27 PM

LION, thanks for posting that photo. That is one heckuva lift bridge. Yes

Rich

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Posted by BroadwayLion on Thursday, April 25, 2019 4:37 PM

LION's EASY Lift Bridge...

 

The lift bridge in question is directly below the Subway bridge above it.

As you can see, the towers are enclosed. You can see the roadway that lifts just above the water.

 

Makes for easy construction.

 

ROAR

 

Add:

It is a four track subway running above 9th Street in Brooklyn, the station is on the bridge structure and is 600' long. The only exit is on the west end of the station. The bridge thakes the subway right over several four story buildings that were there first, so the structure only touches ground on the cross streets and bridges across the buildings.

It was a concrete and steel structure, and the concrete was spalling badly, dropping chuncks on the traffic below. They wrapped the entire structure in that black wrapper, sort of looks like heavy duty tar paper. Concrete can rot, but at least it will not fall to the street below.

 

Now as for the lift bridge, 9th Street is only two lanes wide (plus sideqwalkks) and the towers of said bridge are completely encloxed. They fit entirely under the subway. Only barges and small tow boats will raise the bridge. One cannot imagine a recreational boater putting their craft in the Gowanus Cannal!

 

ROAR

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by gmpullman on Thursday, April 25, 2019 4:13 PM

Excellent progress, Rich BowBowBow

If I didn't already have a Bascule bridge I could easily get the itch bo build a massive vertical lift. 

Hummm Whistling

Have you given thought to cable? One frustration I have with using thread or fishing line is trying to keep each strand taught when threading multiple lines. The Berkshire Jct. Easy Line is great in this respect but, upon close inspection, you can see that it has a flat cross section. 

Thanks for the photos and updates!

Regards, Ed

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Posted by mbinsewi on Thursday, April 25, 2019 10:51 AM

Looking good Rich.

You have a different tower base situation than Frank's, his are right out there, and on a totally seperate piling/foundation,  while yours are bit more obscure, on the shore line with much of it sort of hidden.

Mike.

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Posted by richhotrain on Thursday, April 25, 2019 8:24 AM

I have completed the two decks that will be installed at the base of the towers. The fitting, cutting and painting is done. So now, I just have to glue the front and back sections of the towers to the decks.

Many thanks to Frank, Ed and Mike for their support and advice on this critical step.

Rich

P1010875.jpg

P1010876.jpg

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