Bridges made of Rail Cars 2

[civilman72]

I'm doing a preliminary alternatives analysis for replacement of a 38' span steel-beam bridge, and one of the alternatives I'm exploring is replacing with used rail cars. It seems to be somewhat common and appears to offer some significant cost savings.

I'm a civil engineer (not a structural) so I may not be able to get into some specifics, and am really only concerned with overall pros and cons along with preliminary costs for comparison sake. Does anyone have any general comments or past experience utilizing rail cars for a bridge replacement that I may find helpful? Any hidden costs that I may be missing?

 

[bimr]

http://www.prsx.com/convert.html

If the bridge width is not a problem, if the deck material (wood) is not an issue, the bridge appearance is acceptable and the maintenance requirements (difficult to repaint), then the railcar bridge may work.

 

[dhengr]

Civilman72:
Yes, it can be done, and has been done quite successfully in many instances. It is not something that will easily meet every AASHTO code and std. criteria, so you need a county engineer, or whoever, who will work with you on this. Certainly depends on the types of traffic, loadings, etc. The biggest problem is finding good railcars of the right type. And, you would like identical (sister) cars, so you are not checking and changing and adopting ever single detail and condition on side by side cars, which make up the bridge, but don’t act quite the same. You need cars which are in fairly good condition, not something which is only fit for the junk yard. Contact me at rwhaiatcomcastdotnet. There are several companies which kinda claim to specialize in these railcar bridges, and they seem to know the availability of quality retired cars. There was a good long thread on this exact topic a couple years ago. I’d search in the civil or structural forums for it. I participated in it at considerable length, and have a fair background in railcar design. When I get a chance I’ll look around and see what I can dig up.

 

[dhengr]

Civilman72:
The thread I’m thinking of was in the Bridge engineering Forum, thread #607-302915, Quick Bridges.

thread607-302915

 

[civilman72]

Good stuff, thanks guys. I actually already reached out to Paragon as they seem to have a fair amount of experience with rail car bridges. I'm also the County Consulting Engineer, so I'm kind of on my own on this one.

My general take in reviewing the other thread and other miscellaneous items is that these rail car bridges are best used on low-volume roads. The road I'm looking currently at is considered a Minor Collector by our County Road Standards, with a current ADT of 1200, so I'm hesitant to further explore this as a viable option for this project. However, the county has many low-volume roads where this might be a great application so I may continue to explore this type of bridge replacement option.

 

[BUGGAR]

You can always load test them:

Client has idea for cheap bridge using an old rail car. Brave young engineer checks it out and designs abutments for it. Contractor builds. County says load test it. Brave young engineer has contractor order up a full legal load of gravel and send it out to the bridge. Brave young engineer, as a show of his courage and confidence in his knowledge, stations hisself under the bridge with the level rod overhead while the gravel truck crosses. Much creaking and groaning as the truck crosses and stops midspan. Brave young engineer is measuring 0.30” defection now, secretely praying no one can see the stark terror in his eyes. But it’s holding!! Brave young engineer was right after all, and he is in no danger under HIS bridge! Then the gravel truck driver releases the air brakes with a great loud shrieking “SQWHOOSH!!” accompanied with huge clouds of dust billowing off the sides of the bridge. Brave young engineer is suddenly neither.

Seriously, we did several in Washington State. The Department of Fisheries was the most important to deal with. Knowing the steel grade and weldability is always an issue.

 

[RocketRed]

We have been involved in quite a few of these and in a lot of cases they are more trouble than they are worth. Best success we have had has been in agricultural or single family residential settings (like one house across a creek). Definitely talk to the county roads engineer before you get too far down the path with one. They have always came to us with a stamp for the superstructure but getting rails and abutments that fit the geometry of the actual approach situation sometimes was a bugger.

 

[eea]

Wow, this is on a public road? You don't have a State Bridge Office? No way this would fly with FHWA, DOT, ...

Unless it was for my personal residence's driveway, I'd stop immediately. Just run a life expectancy and do some cost benefit analysis and I'm sure a new structure would put you money ahead.

 

[civilman72]

eea: Just doing my due diligence early on in the process. Based on my research and comments from this site, rail cars are not being considered for this application.

 

[eea]

Good to hear. My experience with interfacing with rural local officials, is that they'll try to make a bridge out of a barn door. I can't tell you how many old boiler tube culverts blew out during the floods of '13 in my region. 15 minutes of StreamStat and a little FHWA Hydraulic Toolbox and stuff is a least roughly sized rather just "shot from the hip". Our State Bridge Office will tell you horror stories of homebrew township structures. NBIS, what?