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Scratchbuilding Towers for a Vertical Lift Bridge

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Scratchbuilding Towers for a Vertical Lift Bridge
Posted by richhotrain on Friday, April 05, 2019 5:28 PM

I am in the process of building a vertical lift bridge based upon the PRR bridge over the South Branch of the Chicago River in downtown Chicago. This is the prototype.

PRR-Bridge-II.jpg

I began this project by building the bridge itself, using three Walthers Cornerstone Arched Pratt Truss Bridge kits, as detailed in the following forum thread.

http://cs.trains.com/mrr/f/88/t/274913.aspx

Now, the challenge is to build the towers. They won't be skewed like the prototype, but more rectangular like most vertical lift bridges. The main superstructure of the towers will be accomplished using Central Valley Model Works Heavy Laced Beam kits.

I will post my progress on this part of the project as I move along.

Rich

Alton Junction

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Posted by richhotrain on Friday, April 05, 2019 6:18 PM

I will be using Central Valley Model Works Heavy Duty Laced Bridge Girders (#1900-5) to build the tower superstructures. 

One of these kits contains 5 sprues, and each sprue contains 2 solid beams, 6 large X-braced beams and 3 small V-braced beams. Actually, these are half beams that need to be joined together to form a single finished beam.

P1010843.jpg

I will be joining X-braced beam halves to solid beam halves to form the vertical and diagonal beams. I will be joining two x-braced beam halves together to form the horizontal beams and joining two V-braced beam halves together to form the horizontal cross supports.

So, in total, each kit will have enough parts to form 10 solid beams, 10 X-braced beams, and 10 V-braced beams. My estimate is that I will need 232 individual parts to build the two tower superstructures. So, that means that I will need to purchase 8 kits.

This will be tedious work because I need to paint the inside of each half beam before gluing the half beams together to form single finished beams. The insides of the joint beam halves need to be painted, since they will be visible through the lacings.

Rich

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Posted by caldreamer on Friday, April 05, 2019 6:29 PM

That is an easy scratch building project using Pastruct and/or Evergreen sturctural pieces.  Try building an ore hullett.  I did and it took me three months to build. I used the article in the October 1997 RMC.  It is really a complicated beast.

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Posted by hon30critter on Friday, April 05, 2019 6:30 PM

Hey Rich,

You have already proven your bridge building skills so I'm looking forward to following your building of the towers. Great project!!Thumbs UpWowYeahThumbs UpBow

I am about to start building a bridge for the club which will be 83" long with an easement in the curve. The bridge starts with a Central Valley 200' truss bridge and then uses an ME 85' plate girder followed by a series of 30' plate girder sections on the bents with 50' plate girder bridges between the bents. I have never attempted anything like this before but having seen what modellers like you have done, I'm not worried that I can pull it off.

Dave

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Posted by richhotrain on Friday, April 05, 2019 6:38 PM

caldreamer

That is an easy scratch building project using Pastruct and/or Evergreen sturctural pieces.  Try building an ore hullett.  I did and it took me three months to build. I used the article in the October 1997 RMC.  It is really a complicated beast.

 

An easy scratch build project?? Ooh, that hurts. Smile, Wink & Grin

I'll tell ya what. Post some photos of your ore hulett for my needed inspiration. I would have no objection to you posting some photos on this thread. It would be fun and instructive to see them.

Rich

Alton Junction

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Posted by richhotrain on Friday, April 05, 2019 6:40 PM

hon30critter

Hey Rich,

You have already proven your bridge building skills so I'm looking forward to following your building of the towers. Great project!!Thumbs UpWowYeahThumbs UpBow

I am about to start building a bridge for the club which will be 83" long with an easement in the curve. The bridge starts with a Central Valley 200' truss bridge and then uses an ME 85' plate girder followed by a series of 30' plate girder sections on the bents with 50' plate girder bridges between the bents. I have never attempted anything like this before but having seen what modellers like you have done, I'm not worried that I can pull it off.

Dave 

Thanks, Dave.

I have to say, building an 83" long bridge with an easement in the curve is going to be some kind of challenge. I hope you will post your progress on that project. That 83" long bridge will dwarf my 30" effort.

Rich

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Posted by mbinsewi on Friday, April 05, 2019 7:51 PM

caldreamer
That is an easy scratch building project using Pastruct and/or Evergreen sturctural pieces. 

OK then....Confused  nothing like some positive encouragement.

Can't wait to see as you progress with the tower build, Rich.

And actually, I'm waiting to see some of the Hulett. 

Mike.

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Posted by hon30critter on Friday, April 05, 2019 8:18 PM

richhotrain
I have to say, building an 83" long bridge with an easement in the curve is going to be some kind of challenge. I hope you will post your progress on that project. That 83" long bridge will dwarf my 30" effort.

Actually Rich I think your project is much more challenging. The length of my bridge doesn't really make it more complex. You are scratchbuilding. I am simply making some standard modifications to ME components. I think my project will be more tedious than difficult. I have to figure out the instructions for building the bents but once I have those down pat it will just be a process of repetition. I have to shorten the bents by about 1 1/4" so that will require some contemplating. The curve will be easy to duplicate because the  plywood roadbed is already in place where the bridge will be. We are going to imprint the track position on a sheet of 1/2" rigid foam so it should be easy to mitre the deck girder bridges to match the curve.

Maybe I am being naive. It wouldn't be the first time.

Dave

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Posted by richhotrain on Friday, April 05, 2019 8:27 PM

mbinsewi
 
caldreamer
That is an easy scratch building project using Pastruct and/or Evergreen sturctural pieces.  

OK then....Confused  nothing like some positive encouragement.

Can't wait to see as you progress with the tower build, Rich.

And actually, I'm waiting to see some of the Hulett. 

Mike. 

LOL

Mike, I just hope that Cal is right. I prefer easy to challenging.

Rich

Alton Junction

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Posted by richhotrain on Friday, April 05, 2019 8:30 PM

hon30critter
 
richhotrain
I have to say, building an 83" long bridge with an easement in the curve is going to be some kind of challenge. I hope you will post your progress on that project. That 83" long bridge will dwarf my 30" effort. 

Actually Rich I think your project is much more challenging. The length of my bridge doesn't really make it more complex. You are scratchbuilding. I am simply making some standard modifications to ME components. I think my project will be more tedious than difficult. I have to figure out the instructions for building the bents but once I have those down pat it will just be a process of repetition. I have to shorten the bents by about 1 1/4" so that will require some contemplating. The curve will be easy to duplicate because the  plywood roadbed is already in place where the bridge will be. We are going to imprint the track position on a sheet of 1/2" rigid foam so it should be easy to mitre the deck girder bridges to match the curve.

Maybe I am being naive. It wouldn't be the first time.

Dave 

Dave, just be sure to post on your progress. I, for one, love to see all kinds of structure building, especially kitbashing and scratch building.

Rich

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Posted by hon30critter on Friday, April 05, 2019 8:48 PM

richhotrain
Dave, just be sure to post on your progress. I, for one, love to see all kinds of structure building, especially kitbashing and scratch building.

Will do!

Dave

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Posted by "JaBear" on Friday, April 05, 2019 9:14 PM

Lift bridge by Bear, on Flickr

"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."

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Posted by zstripe on Saturday, April 06, 2019 3:02 AM

You are a card Bear!.........LOL

Rich,

You will find it much easier to build those CV girders if You build a right angle jig, to hold them square and in place while glueing, I know I did. Also make sure You Read the instructions thoroughly, because they will give You tips on what to use to keep the lattice work even......drill bit sizes. I made my jig out of 1x2 pine and a 5/16ths square piece of pine screwed to the 1x2. Then just brushed a bead of adhesive down the seam, capillary action did the rest. I used Plastruct orange bottle.

After making the jig, I found many more uses for it.

Take Care! Big Smile

Frank

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Posted by richhotrain on Saturday, April 06, 2019 5:48 AM

zstripe

make sure You Read the instructions thoroughly, because they will give You tips on what to use to keep the lattice work even......drill bit sizes.

 

Instructions? Ha, you're looking at 'em.  Not much there, so easy to read thoroughly.
 
Rich
 

Alton Junction

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Posted by richhotrain on Saturday, April 06, 2019 6:42 AM

I have made a template to faciltate building the towers.

What I simply did was to draw the contemplated dimensions and trace the parts needed to complete the face and rear portions of each tower on a Masonite board.

Then, I clamped wood strips to hold the parts in position. The trickiest part is forming the X-brace across each "box". Gussets will hide imperfections in the fitting process.

Rich

P1010841.jpg

P1010842.jpgP1010835.jpg

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Posted by ROBERT PETRICK on Saturday, April 06, 2019 9:04 AM

I want to add one more vote in favor of posting progress photos, mainly for inspiration to others, but also out of curiosity and general interest. Ours is a visually intensive hobby.

Side note to OP Rich: glad you decided to ignore the skewed aspect of the prototype. No sense driving yourself nuts; plenty of other things to worry about. My goal is to try to capture the essence of the scene, and modifying reality to suit is not really a big deal.

Photos!

Robert 

LINK to SNSR Blog


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Posted by mlehman on Saturday, April 06, 2019 10:17 AM

Lift bridge by Bear, on Flickr

 

Well, there is a submarine that's been sitting dead at the curb in the basement of the Museum of Science and Industry. Could patch the extra holes they cut in it, hotwire it - common enough in Chicago - but getting it out of that hole would be a neat trick.

Rich is wise to make the piers non-skewed. The twin lift towers will still be tricky, as they must be both vertical and parallel. Is there a nice solid base to build on here yet to hold all in alignment, mount the drive mechanism on, etc? Then have the whole shebang drop into the location to then attach to the approaches?

Mike Lehman

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Posted by zstripe on Saturday, April 06, 2019 10:44 AM

Rich,

I forgot they don't have any tips on the ones You have. The ones I used do, 1902-5. I wound up getting all the ones they made for different projects. Used all kinds of sizes in the Rolling Lift Bridge bash:

Pic' may be clicked on for larger view.

Take Care! Big Smile

Frank

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Posted by richhotrain on Saturday, April 06, 2019 11:17 AM

zstripe

Rich,

I forgot they don't have any tips on the ones You have. The ones I used do, 1902-5. I wound up getting all the ones they made for different projects. Used all kinds of sizes in the Rolling Lift Bridge bash

I will say this, the total absence of instructions and tips lends itself to maximum creativity.

Rich

Alton Junction

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Posted by richhotrain on Saturday, April 06, 2019 11:52 AM

mlehman

Rich is wise to make the piers non-skewed. The twin lift towers will still be tricky, as they must be both vertical and parallel. Is there a nice solid base to build on here yet to hold all in alignment, mount the drive mechanism on, etc? Then have the whole shebang drop into the location to then attach to the approaches? 

Two comments.

One, I do not intend to make the lift operable. That bridge will just sit motionless on my layout.

Two, I have never fully understood why the engineers designed the towers to be skewed. True, the bridge crosses the river where it runs on an angle, but the towers still could have been built in non-skewed fashion. I believe that a skewed design was selected to avoid having to make the bridge longer (and heavier) if the towers were set further back on solid ground.

Rich

Alton Junction

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Posted by richhotrain on Saturday, April 06, 2019 11:55 AM

ROBERT PETRICK

Side note to OP Rich: glad you decided to ignore the skewed aspect of the prototype. No sense driving yourself nuts; plenty of other things to worry about. My goal is to try to capture the essence of the scene, and modifying reality to suit is not really a big deal. 

Agreed. As I am modeling the river, it runs at a 90 degree angle to the bridge, so no need to skew the towers.

Rich

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Posted by gmpullman on Saturday, April 06, 2019 1:16 PM

This was a pretty tight area, railroad-wise. Engineers probably looked at the additional work to skew the bridge and towers and decided it was worthwhile. As far as material it really wouldn't be too much more of a modification.

Here's everything you'd want to know about 21st. Street Crossing or Alton Junction.

LOTS of great photos!

http://industrialscenery.blogspot.com/2015/02/21st-street-crossing-or-alton-junction.html

...and a gallery of detail photos here:

https://historicbridges.org/bridges/browser/photosviewer.php?bridgebrowser=illinois/sblift/&gallerynum=1&gallerysize=1

 

 PRR_S-Branch-Alton-Jct by Edmund, on Flickr

 There are three skewed lift bridges over the Calumet River, side-by-side. Talk about a modeling challenge!

Thanks for the effort you are making to document your work on this project, Rich Yes

Cheers, Ed

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Posted by mlehman on Sunday, April 07, 2019 12:13 AM

Rich,

That does make things much simpler. The prototype's limited, if any (??), movement at this point certainly suggests that is a convincing option.

As for the skew, IIRC it was much more obvious why things were that way back in the mid-70s when I first went through them. There were the rail lines that Ed helpfully provided the sketches for, but the water traffic had clearly also been a factor in earlier days. Bringing all those connections together was Chicago's big strength, packing things in densely with things like that skew was how this was achieved.

Mike Lehman

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Posted by mbinsewi on Sunday, April 07, 2019 6:42 AM

Ed's second link shows just about every detail there is for modeling the bridge, wow, what a collection!

Great stuff!

Mike.

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Posted by richhotrain on Sunday, April 07, 2019 9:09 AM

mbinsewi

Ed's second link shows just about every detail there is for modeling the bridge, wow, what a collection!

Great stuff!

Mike. 

Yep, I agree. I found that link several years ago, and it has been invaluable to me as I contemplated scratchbuilding the bridge and towers. The close up photos of that structure are extremely informative about the actual construction methods.

One thing that I find interesting about the towers is that there seems to have been no set pattern when it came to designing beams or gussets. If you look at a tower as a system of boxes stack atop one another, the types of beams used seem to vary from one box to another. And, even the gussets vary in shape from one box to another. That left me initially bewildered over how to design towers with a more repetitive pattern to simplify construction.

Rich

Alton Junction

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Posted by richhotrain on Sunday, April 07, 2019 10:49 AM

I finished the front side of one tower, so 1 side down and 7 to go. I do like the overall look of it, and I am satisfied with the types of beams that I have selected to capture the look of the prototype.

I am reasonably happy with the fit of the inidividual parts, though not entirely pleased. So, I am going to fall back on one of my favorite moel railroading expresssions, "it is good enough", at least for a first attempt.

I still have to make three more "face" sides, so I will choose the best two face sides to use on my layout, and the other two can be the back sides, away from the camera and layout visitors.

Go easy on me.

Rich

P1010848.jpg

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Posted by mrrdad on Sunday, April 07, 2019 11:33 AM

Rich,

That looks fantastic!

Being a former Chicago area resident, I know the area you are modeling. I love what you're doing. Thank you so much for sharing.

Ed

Modeling the B&O Chicago Terminal Railroad in the 1950's

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Posted by richhotrain on Sunday, April 07, 2019 11:51 AM

mrrdad

Rich,

That looks fantastic!

Being a former Chicago area resident, I know the area you are modeling. I love what you're doing. Thank you so much for sharing.

Ed 

Thanks, Ed, glad to read that you are enjoying this project. As a lifelong Chicagoan, born and raised in the city, and later married and transplanted into the southwest suburbs, big city railroading is all I know.

Before retiring, I rode the Metra Rock Island downtown to work each day for years, crossing bridges in Blue Island and passing by the PRR lift bridge and the SCAL/BOCT bascule bridges. Pulling into downtown LaSalle Street Station, Grand Central Station was on the left and Dearborn Station was on the right. A lot is gone now, but the bridges all remain.

Rich

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Posted by Track fiddler on Sunday, April 07, 2019 1:38 PM

Great looking start on the side tower RichYes  Good to see your project moving into phase 2.

I wouldn't model the right side tower in a parallelogram configuration eitherZip it!  That would definitely complicate things, quite a bit.

I think you made a good choice in your choice of materials as well.

TF

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Posted by richhotrain on Sunday, April 07, 2019 2:49 PM

Track fiddler

Great looking start on the side tower RichYes  Good to see your project moving into phase 2.

I wouldn't model the right side tower in a parallelogram configuration eitherZip it!  That would definitely complicate things, quite a bit.

I think you made a good choice in your choice of materials as well.

TF 

Thanks, TF.  At one time, I had considered trying to model a more exact replica of the area south of downtown Chicago up to and including the so-called "Alton Junction, just a few yards south of the PRR lift bridge. That fantasy included a skewed PRR bridge over an angled South Branch of the Chicago River. But, reality set it in terms of time and space, and the acknowledgment that a master craftsman I ain't. I know my limits, so I settled for a rectangular set of towers.

Rich

Alton Junction

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