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Bridge Questions

I some questions related to a largish deck bridge I'm building for my Santa Fe prototype layout. This will be in HO and include three towers with 30' tower spans, two 50' intermediate span and a 90' deck truss span. I'm using a combination of Micro Engineering and Atlas components. Bridge will be open construction, not ballasted deck

In looking at photos of ATSF bridges it seems like most of the larger bridges had walkways on both sides. However, the pictures I have show mostly ballasted deck bridges. So my questions:

· In the 1940's-50's would an open deck girder bridge have had walkways, or only safety platforms? (I consider this bridge to be on a "secondary main line"). · If adding walkways, how are they attached to the bridge. I am considering just extending some of the ties to the width of the track plus walkway, then laying boards over the top and adding railings (Central Valley). Would this approach be prototypical, or would triangular supports bolted to the side of the girders (or truss uprights for the truss span) be better (much more labor intensive!)? · What color would be most appropriate? I have a picture of the Arroyo Seco bridge from about 1950 in silver or aluminum paint, but I recall from my youth in the 1950's a long deck bridge in Santa Ana canyon that was black and had a Santa Fe slogan on it (logos plus "Santa Fe, all the way", I think it was). What was ATSF practice. · Any suggestions on a source of decals for the logo and slogan painted on such bridges - I am thinking about O scale box car decals. · Any other suggestions on such a bridge project you may feel appropriate would be appreciated.

Thanks

Rick Stern

Reply to
Richard Stern
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Hi Richard, I did a quick look through the Bridge and Trestle Handbook by Mallery and I can't find any reference showing the presence or absence of walkways to be era dependent. My guess is that whether a deck bridge had a walkway or not was probably a function of whether the railway wanted one or not. What seemed to be common practice for the railway you are modelling may be a good guide. Where refuges (safety platforms) were used, they were not usually found on bridges less than 100 feet long. The refuges were commonly built on extended ties or supported by timbers placed between the ties as you suggest. Mounting on brackets extended from the side of the truss or girder was also done but not frequently.

Lynn

Reply to
Lynn Caron

Lynn:

Thanks -- I had checked Mallory's book also and didn't find too much help (though it's a great book I've used for a variety of bridge projects).

Just looking at photos, I get the impression that walkways on ballasted deck bridges are about level with the ballast. But my vague recollection of being on a trestle once was that the ends of the ties were showing above the level of the walkway.

Agreed, the individual RR practice is likely most relevant.

rs

Reply to
Richard Stern

At one time the Santa Fe Railway Historical and Modeling Society offered a set of ATSF bridge decals. I don't know if they're stil available, but check with the folks at

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to see if they have them, or will make them available again. Even if the decals are no longer available, their book on ATSF Trademarks and their usage (IIRC) should have a section covering bridges.

As for your questions on the bridges themselves, ATSF seemed to prefer the ballasted deck bridges on main lines. Some information can be found in Kachina Press's "Chief Way Reference Series, Santa Fe System Standards Volume 1." Pages 93-128 cover bridge construction standards, including railings.

Reply to
Sean S

That decision is usually up to the prototype's policy. B&O seemed to favor safety platforms and the WM liked walkways. Walkways add to the cost, but sure make it safer to inspect a train when it's stranded.

The WM used a longer tie every 6th bridge tie to carry the walkway. The B&O, when they did use walkways, added 4x8 timbers extended from between each 4th tie to carry the walkway.

Good question. Seems like the color practice is all over the map. I have seen everything from basic Red Lead to Gray to Aluminium to Buff to Black used by the same road. Personally, I like Aluminium color.

Happy rails,

Roy

Reply to
Roy

As others have said, it's up to individual railroad's policy on that -- or the policy of the predecessor line that built the structure.

But with the length of the bridge you're talking about (fairly long, especially in model railroad terms) walkways would be more likely. A crew has to have access to cross the bridge even when a train is on it, for example, if it had to stop because of a hotbox the crew would need to be able to walk the length of the train to find the problem. Walkways would sometime be used on both sides of the bridge so the crew could inspect both sides of the train.

Here's a walkway detail for open deck structures from the 2002 "Manual of Railway Engineering," by the American Railway Engineering and Maintenance-of-Way Association.

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Although this publication is pretty recent, the detail is pretty classic and applies to almost any era and structure type. Extend every fourth tie, cover with 2" walkway planks, and add a handrail.

Reply to
Mark Mathu

Bridge walkways serve several purposes, among them: to protect personnel working on the bridge, to allow passage of personnel past a stopped train and to allow inspection of a stopped train.

Walkways for personnel protection were normally used only for bridges with more maintenance activity than normal, like moveable bridges or bridges with signal/communication devices on them. Most bridges didn't require enough maintenance activity to justify walkways.

Walkways for personnel passage would be the most common, especially after the removal of roofwalks. Bridges near turnouts and stations will also most likely have walkways. Walkways for train inspection would only be found on the longest and highest bridges.

Look at your proposed bridge from the railroad's perspective, and if any of the above apply, you're bridge should probably have walkways.

The type of walkway is a cost and preference issue. Extending the ties is (relatively) cheap in the short run, but has to be redone everytime the ties are replaced. Steel brackets are more expensive, but will last longer. IIRC, the Santa Fe used long ties with a braced wooden handrail. Most of their steel bridges were black too.

Hope this helps.

Chris Johnson

Richard Stern wrote:

Reply to
Chris Johnson

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