Need to add bridge shoes - are they easy to make?

Model Railroader Prototype information for the modeler
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I have just come into possession of a Great Northern deck girder bridge with wood walkway and handrails by ExactRail, shipped quickly and packaged well (comes already assembled). It’s a really handsome piece but it came unshod. I need to cobble four little bridge shoes for it. If I were a bettin’ man I’d say odds are good that one or more of you have made your own bridge shoes before and are just dying to tell me how you went about it and show me pictures too! Anybody?

Thanks,

-Matt

Sorry if this should have gone in the General Discussion. I wasn’t sure. Feel free to move it, oh Powers that Be.

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These?

https://www.modeltrainstuff.com/Micro-Engineering-HO-80-034-Bridge-Shoes/

Good Luck, Ed

3

How long is the bridge? I don’t know what the requirement is, but around here some of those type bridges didn’t have shoes. There were just plates at the ends of the girders upon which the girders sat.

4

This was something I did not know until I started travelling and photographing everything I saw.

Sure enough, a lot of girder bridges out there do not have shoes. Exactly what I was told I was doing wrong turns out to be a common practice.

-Kevin

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How about these for 9 bucks?

https://www.walthers.com/bridge-shoes-adapters-assortment-kit

Rich

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I never would have thought there were so many words related to bridges:

http://sdrc.lib.uiowa.edu/eng/bridges/WaddellGlossary/GlossS.htm

Shoe: “That part or detail of a span which transfers the load from the end pin to the bearing plate or to the intervening rollers.”

Since every bridge must have something to do that transfer, every bridge will have bridge shoes.

Bridge shoes also have a corollary task: they have to account for the different expansions, both thermal and physical, of the bridge and the ground underneath. Thus they must allow for movement.

On a large bridge, this will be the bridge shoes that are so obvious and are somewhat illustrated by the Micro Engineering ones. I say somewhat, because they are only selling the “anchored” type. There is also the “non-anchored” type. This is to allow for the movement mentioned above.

While the anchored type will commonly have the pin connection shown in the Micro Engineering sample, the other one will have rollers. This is “non-anchored”, and where there will be movement.

If both ends were anchored, the bridge would fail.

I suppose there could be bridge shoes that would practically be invisible, and appear not to be there at all. They would dispense with the rollers, and just go with sliding. Thus there would only be a steel plate on top of another steel plate. Horizontal alignment would have to be allowed for, though. If someone can come up with pictures, I’d sure like to see this. There ARE some short girder railroad bridges, maybe 20’, that might be done that way. Seems like the plates would have to be lubricated, REGULARLY.

To model the apparently unavailable rolling shoe, you can modify the pin type by cutting the pin secti

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You can cobble them together out of anything, even rail.

Or as others have stated I have seen bridges too poor to have shoes.[C):-)]

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In my defense… it was late and I’d had a long workday. It didn’t even occur to me to wonder if someone might SELL them. Yes Wayne, exactly like those. And yes, Rich, those look like a good option, too and at a good price. Maxman and Kevin, I have seen this a few times too recently – bridges without shoes. I’ve only been paying attention to bridges and how they do their bridgey business for about four months, and I started noticing the shoes on everything only after I put a few kits together and had to glue their tiny little booties on. Like you, Kevin, I noted the rule – “ah, I see that bridges must have shoes”. And then I saw a fairly long deck girder bridge with NO shoes. I’m sort of torn. I like the springy look of a bridge with shoes. I reckon I could go take a drive and see what’s doing out in the neighborhood here.

Anyway, thanks guys.

-Matt

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Brent, Ed, gosh, thanks for all those great photos. Brent, I love the rail idea. Got plenty of that handy. Ed, those roller shoes look exactly like trouble waiting to happen. They look positively slippery. I hear the cartoon “slipping on a banana peel” bongo drum roll when I look at those, especially the blue cylinder. But I guess they can’t really roll very far.

My bridge is a GN bridge. I should be able to find one around here in Seattle.

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From Paul Mallery’s “Bridge & Trestle Handbook”:

“One end of a simple bridge is always fixed in place, but the other end is permitted to move as the bridge expands or contracts as the temperature changes…For short-span bridges (60’ (18m) or less) often the expansion-end shoe merely slides on the pedestal and both may be as simple as steel plates.”

60’ is, in HO, 8".

The book has gone through 4 editions, and is an excellent book on the subject.

Ed

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Nope. The other end is firmly anchored. The rolling action is severely constrained.

I believe a railroad deck girder bridge is not noticeably railroad specific. Not a lot of styling options.

Now, through girder bridges…

Ed

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The roller bridge shoes are interesting Ed. You can see they serve their purpose not only for support but more importantly for movement as you stated.

Definitely the movement is minimal but a critical factor shoes provide from season to season otherwise as you also stated the bridge would fail.

It would be interesting to have time lapse photography for a year and watch it in about 30 seconds and I do believe that’s the only way you would ever see it. Minimal but it is there.

This could have already been stated here but It really floored me when I learned 5 - 6 years ago that bridges cause rotation at the shoes. My response, I said “Get Out Of Here!” It takes place on most but even more prevalent on the longer truss bridges.

It was explained to me it is why the larger bridges have split shoes with the pin in the middle and I’m sure the roller shoes work in the same way. The person explaining it to me went on to say put a long board in-between two saw horses and bounce up and down on it for a year and see how worn the board ends resting on the saw horses become.

I then understood how heavy freight trains going over a bridge bow the center down causing bridge rotation. Extremely minimal but must be accounted for.

Bridges are interesting.

P.S. I could be wrong but I think I remember reading the split bridge shoes with the pin in the middle have an oval stamped through the lower one to provide for expansion and contraction. Makes me wonder how often those pins have to be lubricated or changed out?

TF

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To get the genuine hiding, I recommend Paul Mallery’s “Bridge and Tresrle Handbook” (Paul gave me a copy back in the Sixties)

I’m sure he addresses bridge shoes

Bridge & Trestle Handbook by Paul Mallery soft cover Revised edition 1976 Red Co | eBay

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A two-man job:

Erie Bridge Supports by Edmund, on Flickr

Regards, Ed

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Huh. And here I thought it would be a heavy grease and they’d have to jack up the bridge a bit to get it in-between there[(-D]

It comes in a cylinder bucket fed by gravity from a spicket? [:^)]

Must be Kroil then,…Good wonderful stuff! Seeking lubricant.

TF

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See earlier post in this topic:

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I do believe that is an air line coming in from the lower left.

Ed

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I think not.

The roller shoes are meant to allow movement. The pin type does not, and so is used at the rigid end (except, as you have pointed out, for rotation about the pin).

I think the purpose of the split shoes with pin is to make for easier assembly. You just have to place the pin in the already in-place bottom piece, and lower the bridge (with the top piece already attached) downwards. The bridge, being properly designed and fabricated, will line up beautifully.

If you use the other style (the not-split), you either have to insert the pin(s) from the side while holding the bridge up just-so, or you have to have the bridge shoe fully assembled and in place, and you then lower the bridge down and insert a multitude of bolts.

I have seem both of these two latter processes done on container cranes, where the trucks are added to the bottom of the crane during installation. It is NOT the favorite part of the job for the crew–highly stressful.

Ed

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If those things are made in a similar fashion to steam turbine base and sole plates, there is a grease groove (or grooves) machined into the mating surface of one of the plates. One end of the groove has a grease fitting, and the other has a plug that is removed during the greasing process. This acts as a vent.

What I’d really like to know is how that guy with the white shirt and tie manages to not get a spot of grease on him. In 34 years of working around turbines I couldn’t walk within 10 feet of one without getting a smudge somewhere.

That must be a publicity photo.

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His sleeves are rolled up and his hands are dirty.

He’s good! He’s very, very good.

Ed