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Walthers Cornerstone Arched Pratt Truss Bridge

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Posted by richhotrain on Friday, April 5, 2019 5:35 PM

For those who might be interested, I have started work on the towers. I have also started a new thread to detail my progress.

http://cs.trains.com/mrr/f/88/t/275386.aspx

Rich

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Posted by Track fiddler on Sunday, March 31, 2019 7:16 PM

Coming along rather nicely Rich.  The bridge looks like it always was that way.  The result of some fine modeling skillsYes

TF

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Posted by hon30critter on Sunday, March 31, 2019 5:24 PM

mbinsewi
Looking great Rich, when I click on your pics and enlarge them, with all the detail, it's hard to tell what you scratched and added on.  

Yes

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 richhotrain on Sunday, March 31, 2019 2:07 PM

mbinsewi

Looking great Rich, when I click on your pics and enlarge them, with all the detail, it's hard to tell what you scratched and added on. The only reason I know, is because of your earlier pictures and conversation.

Thanks, Mike. I like to enlarge the photos to find flaws and then fixed them. On the other hand, the camera sees what the human eye often does not see, so enlarged photos can be scary to the modeler who has worked hard to build a flawless model.

Rich

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Posted by mbinsewi on Sunday, March 31, 2019 10:14 AM

Looking great Rich, when I click on your pics and enlarge them, with all the detail, it's hard to tell what you scratched and added on.  

The only reason I know, is because of your earlier pictures and conversation.

Mike.

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Posted by richhotrain on Sunday, March 31, 2019 9:59 AM

I have completed the bridge except for some minor touch up. So, now it is on to the construction of the towers.

Rich

P1010830.jpg

P1010831.jpg

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Posted by richhotrain on Saturday, March 30, 2019 1:40 PM

mbinsewi

Looking great Rich.  Yes  So much sheave info!  Who knew?

Mike. 

Thanks, Mike.

Yes, who knew.

I want to thank all of you guys for finding and linking me to these various possibilities. A lot more options to select from that I first thought.

Rich

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Posted by richhotrain on Saturday, March 30, 2019 1:38 PM

Track fiddler

Impressive Rich.  I see you've been busy, moving right along.  Looks great!

TF 

Thanks again, TF. 

I appreciate your encouragement.

Rich

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Posted by gmpullman on Saturday, March 30, 2019 8:44 AM

mbinsewi
Was that structure across the top added later?

Part of the original bridge, Mike. It was built in 1956. Before that the NYC's New York-Chicago main line crossed over the river on a swing bridge with a gauntlet track, effectively bottlenecking the four-track main down to one (can only use one gauntlet at a time!) The PRR used the same bridge to get to the ore docks where the Hulett unloaders used to work. Today it is NS.

On May 8, 1974 the counterweight of the open bridge was struck by Penn-Central eastbound train OV-8 at about 35 mph. I was there a few hours after it happened. Not a good thing to see.

Regards, Ed

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Posted by Track fiddler on Saturday, March 30, 2019 7:55 AM

Impressive Rich.  I see you've been busy, moving right along.  Looks great!

TF

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Posted by mbinsewi on Saturday, March 30, 2019 7:55 AM

gmpullman
He gave us a ride to the top of the towers to watch the fireworks at nearby Edgewater Park!

Wow!  THAT had to be cool!

Was that structure across the top added later?  or is that part of the original bridge.

Mike.

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Posted by gmpullman on Saturday, March 30, 2019 7:45 AM

mbinsewi
Looking great Rich.    So much sheave info!  Who knew?

Yes, excellent model, Rich!

There is some additional counterweights and sheaves to support the power cables which might make for a neat detail if you're ambitious enough Whistling

 NJ_bridge-power by Edmund, on Flickr

I remember being at Bridge One in the Cleveland Flats one July Fourth. I was friends with the operator. He gave us a ride to the top of the towers to watch the fireworks at nearby Edgewater Park!

That was some times to remember! Below is a look at the present-day "Bridge One"

 1028181411 by Edmund, on Flickr

Cheers, Ed

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Posted by mbinsewi on Saturday, March 30, 2019 7:16 AM

Looking great Rich.  Yes  So much sheave info!  Who knew?

Mike.

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Posted by richhotrain on Saturday, March 30, 2019 6:59 AM

Yesterday, I finished installing the top and bottom lacings. Today, I will finish the top x-bracing, and that will nearly complete the bridge except for some minor finishing touches.

Rich

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P1010822.jpg

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Posted by richhotrain on Saturday, March 30, 2019 6:54 AM

zstripe

Edit: While You are on the Plastruct site, look at the gussets. They have no rivet detail, but are at least already cut to size.  

Frank, I just received an order in the mail yesterday from Tichy (via eBay) consisting of Rivet Plates. These are 1 1/2' x 2 1/2" sheets of styrene filled with dimple marks representing rivets. I will see how this works out on the tower construction.

Rich

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Posted by richhotrain on Saturday, March 30, 2019 6:34 AM

Frank and Ed thanks for those suggestions and links. More to think about.

I came across this item from Preiser, a cable drum set of 4 which looks pretty cool, but I cannot find dimensions like diameter and width.

https://www.preiserusa.com/Preiser-17117-Cable-drums-and-crates-Kit

Rich

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Posted by gmpullman on Saturday, March 30, 2019 6:06 AM

richhotrain
Those sheaves are $3.50 a pair, so if I wind up installing 4 cables on each sheave, that would require 16 pairs of sheaves for a total cost of $56.00.

I came across these neat-looking gears, cogs & wheels a while back at Amazon, maybe others:

https://tinyurl.com/yypny39j

There's a dozen or more designs in each bag and maybe six or eight of each design. Maybe these could be a starting point for your sheaves?

 cog_2 by Edmund, on Flickr

If you found a thin-wall corrugated tubing, then stuffed it with these gear hubs, maybe with the teeth sanded off you might get a neat looking assembly. Or you could wrap them with grooved styrene sheet cut into a strip. Put the joint at the bottom, out of view.

 cog_3 by Edmund, on Flickr

These that I stuck onto a nail are five HO feet in diameter:

 cog_4 by Edmund, on Flickr

IMHO, the Tichy and the old SS Ltd "Mine Head" sheaves are too spindly looking to support the massive weight of a lift-bridge.

 cog_ss-ltd by Edmund, on Flickr

The two on the left might work but, if you can find them, they are about double the cost of the Tichy ones. It is too bad the old Life-Like gears are so large (ten-feet in HO) as I believe the spoke pattern is perfect for a lift bridge, although, the big old NYC RR bridge at the mouth of the Cuyahoga River here in Cleveland has sheaves that are at least that size. (NJ, too, see below).

 Cog-Life-Like by Edmund, on Flickr

Here's a look at the Newark Bay Lift Bridge on the C. RR of N.J.

 NJ_bridge by Edmund, on Flickr

Looks like there are guards over the tops of the sheaves so you really don't see the cables or grooves. But it would be a nice detail to see them on a model.

 NJ_bridge-sheave by Edmund, on Flickr

Hope that helps—

Good Luck, Ed

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Posted by zstripe on Saturday, March 30, 2019 4:56 AM

Rich,

If cost is Your concern, take a look at this Plastruct link and on page 37 for Handwheels/Disc's. You could make Your own sheaves with a spoke on the outside and disc. in the middle, followed by another spoke and so on. Should be a lot cheaper than the Tichy parts. And No.....I would not try to make them out of thin styrene, not when there are offerings already out there. Cutting a round disc from sheet styrene is pretty hard to do and cutting from a tube isn't so easy either.

http://www.plastruct.com/catalog/Vol_10_CatalogSMFL.pdf

Take Care! Big Smile

Frank

Edit: While You are on the Plastruct site, look at the gussets. They have no rivet detail, but are at least already cut to size. Page 18

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Posted by richhotrain on Saturday, March 30, 2019 3:47 AM

zstripe

Rich,

The CMR bridge main span is 4 3/4'' wide. The hoist platform is 5'' wide x 1 1/2'' and it holds the 16pieces for the sheaves, the motors, gears and the shack, along with a three sided railing. So if You were to make yours 5'' wide and 4'' long, you would have more than enough room to put anything You want up there. Remember...part of the sheaves overhang the edge on both sides so the cables do not rub on the structure. 

Yes, I agree that the sheaves should overhang the platform to allow cable clearance, and I plan to do that. There is a lot to think about in the planning stage, so I appreciate the reminder.

zstripe

I'm sure there must be at least a partial floor on the hoist platforms.......it would be awful dangerous to do any maintenance on moving parts, if you just had girders to walk around on.

I'm not so sure about the partial floor on the hoist platforms. From the photos available of the PRR bridge/towers, and the overhead views using Google Maps, it certainly appears that the sheaves are mounted on girders with no floor across the top of the tower. I could be mistaken here, but it sure looks like what I have described. I will need to researching this further.

zstripe

One sheave holds one cable. The sheaves closest to the main span, are the motorized ones, the ones holding the counter-weight are idlers for a 8 pulley system. That's going to add up in cost....so be prepared. 

I am concerned about space limitations up at the top of the towers, and cost becomes an issue as well. Those sheaves are $3.50 a pair, so if I wind up installing 4 cables on each sheave, that would require 16 pairs of sheaves for a total cost of $56.00. That seems excessive just to complete the sheave portion of the project. I have considered scratchbuilding the sheaves to save money. One thought that I have had is to fabricate the sheaves out of thin wall plastic pipe. Thoughts?

Rich

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Posted by zstripe on Friday, March 29, 2019 5:39 PM

Rich,

The CMR bridge main span is 4 3/4'' wide. The hoist platform is 5'' wide x 1 1/2'' and it holds the 16pieces for the sheaves, the motors, gears and the shack, along with a three sided railing. So if You were to make yours 5'' wide and 4'' long, you would have more than enough room to put anything You want up there. Remember...part of the sheaves overhang the edge on both sides so the cables do not rub on the structure. Look at the pic', you can see how they overhang. The four sets on Your bridge should do the same.

I'm sure there must be at least a partial floor on the hoist platforms.......it would be awful dangerous to do any maintenance on moving parts, if you just had girders to walk around on.

Don't start over thinking.........

Take Care! Big Smile

Frank

EDIT: This pic' should give You a better shot of the sheave overhang:

They can be clicked on for a larger view.

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Posted by richhotrain on Friday, March 29, 2019 4:15 PM

zstripe

Rich,

Well to be honest, yet realistic, I believe a minimum of three cables per sheave would be realistic. Those Tichy ones should be able to be butted together, that is how the CMR ones are designed. I actually added one to the outside of an outside one so the spacing was eliminated at the top of the hoist platform. Meaning....they wanted you to put seven halfs together to form one set. But when you did that, there was a gap between the end sheave and the mount......I did not like the gap so I added an end to one side of each set.

If You look at the pic' and count starting from the left, You will see what I am talking about. The unpainted parts were scratchbuilt by Me and the brass shaft was inserted into the sheaves into the end brace. They were also designed to keep the shacks in alignment and stop light bleed through the edges. The holes in the kit sheaves are square so they all line up exactly the same.......but... a square part will not fit into the round holes of the gearing I used, so I used brass 1/16'' rod for the shafts and only used the square shafts supplied to keep the sheaves all the same while the adhesive dried.......worked fine! 

Frank, thanks for that additional information and photos. It is all very helpful. I am going to come back to you when I reach the platform stage on the towers to get your opinion on the appropriate number of cables. I just cannot decide at this point. 

I have determined though the the towers should be 5" x 6" so that will have some decided effect on the size of the sheaves and the number of cables. One other consideration to take into account is the fact that the four sheaves on each tower do not sit on a single platform. The "platform" at the top of each tower is actually a set of four girders. The left side sheaves sit on one girder and the right side sheaves sit on a separate, parallel girder, so space is limited.

Rich

 

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Posted by zstripe on Friday, March 29, 2019 7:56 AM

Mike,

Thanks for the comments. I'm pretty sure those photos were in one of My last posts in that thread. I did not post a final picture of the different color ties, because the bridge is at the Grandkids house layout so I could set-up and lay the track to it.......that is why I built it, for them......I have enough bridges on what's left of My layout.

If no one complains.......how about a sneak peek!

British Battleship HMS Prince of Wales.

The deck is real laminated wood:

Take Care! Big Smile

Frank

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Posted by mbinsewi on Friday, March 29, 2019 7:32 AM

Frank, these last pictures you've shown, I think, are the first pictures I've seen of the completed bridge, with ladders and railings, and buildings in place.

Excellent!

I can't wait to get a glimpse of that ship!

Mike.

 

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Posted by zstripe on Friday, March 29, 2019 7:25 AM

Rich,

Well to be honest, yet realistic, I believe a minimum of three cables per sheave would be realistic. Those Tichy ones should be able to be butted together, that is how the CMR ones are designed. I actually added one to the outside of an outside one so the spacing was eliminated at the top of the hoist platform. Meaning....they wanted you to put seven halfs together to form one set. But when you did that, there was a gap between the end sheave and the mount......I did not like the gap so I added an end to one side of each set.

If You look at the pic' and count starting from the left, You will see what I am talking about. The unpainted parts were scratchbuilt by Me and the brass shaft was inserted into the sheaves into the end brace. They were also designed to keep the shacks in alignment and stop light bleed through the edges. The holes in the kit sheaves are square so they all line up exactly the same.......but... a square part will not fit into the round holes of the gearing I used, so I used brass 1/16'' rod for the shafts and only used the square shafts supplied to keep the sheaves all the same while the adhesive dried.......worked fine!

Take Care! Big Smile

Frank

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Posted by richhotrain on Friday, March 29, 2019 5:34 AM

zstripe

Rich,

It would probably not be a bad idea, to wait until You get the Tichy parts and put four or three of the sheaves together, to see how far apart the holes would have to be in the top of the bridge ends, so they will all be uniform and perpendicular to one another, which is a must. Once together, they would stick out like a sore thumb, if they were not.

Take Care! Big Smile

Frank 

Frank, you raise an interesting issue regarding the number of sheaves and the number of cables used to lift and lower the bridge.

On the CMR vertical lift bridge that you built, which is significantly different from the PRR vertical lift bridge that I am building, there are 2 angled towers, supporting 4 sheaves with each sheave supporting 3 cables, or a total of 12 cables. This arrangement is true to the prototype.

There was a similar angled tower lift bridge in Chicago at Halsted Street for many years, although it had 4 cables per sheave, or a total of 16 cables.

The PRR vertical lift bridge in downtown Chicago has 2 towers with 4 sheaves on each tower, or a total of 8 sheaves. Each sheave supports 16 cables, or a total of 32 cables per tower, for a grand total of 64 cables.

So, for me, the issue becomes one of selective compression. How many sheaves do I install and how many cables per sheave do I install? The minimum, of course, would be 2 sheaves, one per tower, or a total of 4 sheaves. However, it would be much more realistic to install at least 4 sheaves per tower, or a total of 8 sheaves. As far as cables are concerned, if I limited the number of cables to 1 per sheave, that would require 8 cables. So, in my mind, I ask myself, where do I start and where do I stop?

I really do like the Tichy sheaves, but they are designed to hold a single cable per sheave. On the prototype, each sheave is wide enough with sufficient grooves to support multiple cables. Your CMR sheave is a good example. A single sheave has 3 grooves to support 3 cables. 

So, I am struggling with this aspect of the project. How many sheaves and how many cables?

Rich

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Posted by zstripe on Friday, March 29, 2019 4:43 AM

Rich,

It would probably not be a bad idea, to wait until You get the Tichy parts and put four or three of the sheaves together, to see how far apart the holes would have to be in the top of the bridge ends, so they will all be uniform and perpendicular to one another, which is a must. Once together, they would stick out like a sore thumb, if they were not.

Take Care! Big Smile

Frank

 

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Posted by richhotrain on Friday, March 29, 2019 4:14 AM

Frank, had you not mentioned it, I would not have thought about it until it was time to connect the cables. Since I am basically kitbashing multiple bridge kits, I have been following the general construction principles of the basic kit. The only trouble with that approach is that the basic kit is not designed as a vertical lift bridge, so it makes no provision for an end beam to hold the cable mounts.

Stay with me.

Rich

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Posted by zstripe on Friday, March 29, 2019 3:41 AM

richhotrain
So, the ends of the bridge were not designed to be boxed but, rather, angled with an "end post" and X-braced struts across the top of the truss sides. So, I will need to fashion an end brace to provide a surface for the cable holders

Rich,

That's exactly why I brought up the cable holes at this time......doing a little thinking ahead of You.....so to speak!

Take Care! Big Smile

Frank

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Posted by richhotrain on Thursday, March 28, 2019 11:31 PM

zstripe
  
richhotrain
Regarding the holes in the end braces for the cables, can you elaborate on that point a little more. I'm not sure that I understand your point. Rich 

Rich,

Look at the top of the end of the bridge in the pic', there are three holes in the top end piece for the cables that lift the bridge. If You drilled them before gluing the end pieces on it will be easier to  have both sides the same by using one as a template for the other side. Plus there will be less stress on them when pressing down on the bit to drill the holes. The holes in the CMR bridge were already in the end pieces:

ahh, OK, I see now what you are saying. Your point on the end brace raises an interesting issue with this particular bridge. Out of the box, it is not designed to be a vertical lift bridge. So, the ends of the bridge were not designed to be boxed but, rather, angled with an "end post" and X-braced struts across the top of the truss sides. So, I will need to fashion an end brace to provide a surface for the cable holders.

Rich

Alton Junction

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