Using Railroad Track for bridge beams

   / Using Railroad Track for bridge beams #21  
I have two creek crossings, one is down to bedrock and I just put #57s down either side, other I used steel corrugated pipe, 36" X 20ft. On upper end where creek starts at spring. I'd sell RR steel.
 
   / Using Railroad Track for bridge beams #23  
I'm in - It is far too flexible. One time I was looking for an I beam to move a concrete septic tank, weight was about 10K. Went to the steel yare and looked at a 20' 6" I beam. When they picked it up, it flexed like crazy. i had to use 12"19lb to get the strength.

Rail would be a nightmare is my guess. Take a LOT of support and support to keep it from turning under load.
 
   / Using Railroad Track for bridge beams #24  
Can you post a single example of structural railroad track? And a railroad track in some more complex plan doesn’t count. Just track laying flat down as a beam like the op is planning.
Railroad track around is commonly used in retaining walls

from comments here, most of you have not seen a bridge beam prior to lateral bracing installation. They can be move with your hand
 
   / Using Railroad Track for bridge beams #25  
Railroad track around is commonly used in retaining walls

from comments here, most of you have not seen a bridge beam prior to lateral bracing installation. They can be move with your hand
Maybe but my 2 bow a few inches down with just ONE dog standing on it, or a person. No sway side to side but lots of up and down, almost like a rope bridge.
 
   / Using Railroad Track for bridge beams #26  
Nice of the company to give away money like that, offer the company to take the whole lot and get it in writing. Start calling around scrap yards for the best price on heavy melt, I'm sure they will pick up, give you some decent cash, and you won't have to lift anything heavier than your cell phone.
From what I heard (at least in my area) most steel scrappers won’t take rail.
 
   / Using Railroad Track for bridge beams #27  
Railroad track around is commonly used in retaining walls

from comments here, most of you have not seen a bridge beam prior to lateral bracing installation. They can be move with your hand

They also use concrete pre cast blocks for retaining walls and I think we can all agree those won’t make a good bridge.
 
   / Using Railroad Track for bridge beams #28  
41 years experience messing with rail. Your 90lb rail doesnt weight 90lbs per ft, it weighs 90lb per 3 ft. Just supported on each end, it will bow like a sting under its own weight. Even 132lb rail will bend and flop when its hooked to a crane. Selling it to scrap yards isnt easy either. Most reputable scrappers wont touch it unless you can document where it came from because they cant resell it without proper documentation. Altho I do know a few that will break it up into chunks and hide it inside car trunks and such. Another thing to consider is rail is very brittle and will break, especially in cold weather. Rail makes great cattle crossings when its laid perpendicular to the roadway but unless you can put some support under it, I wouldnt consider it for a bridge.
 
   / Using Railroad Track for bridge beams #29  
You could have the top rail straight and have one below it with an upward arch that would give it cantilever strength, but that would have each side at nearly 2000 pounds, kind of hard to get across the span to place.
At any rate, I hope you glom onto the free rail anyway, you never know...
Rail is 90# per yard, not ft.

So two 20' runs per side wouldn't come close to a ton.
 
   / Using Railroad Track for bridge beams #30  
Im not going to touch on material quality.....brittleness, flexibility, etc. I'll simply stick to listed material properties.

And 90# rail is 5-5/8" tall and has a moment of inertia of 38.7.

Which makes it slightly stronger than S7-15.3 I-beam which is 36.7.
And falls between w6x16 @ 32.1 and W6x20 @ 41.4

That said......With 4500# at midspan of a 20' section per side.....your 90# rail would deflect 1.12" and would see bending stress ~21,000psi. In "engineering" terms you would typically want deflection to be less than L/360. Which is "length in inches" / 360. So you want to shoot for something that wont flex more than ~0.667"

I'd say the rail falls a little short of this goal.

A w8x21 with a moment of inertia @ 75.3
A w10x17 or a w12x14 are all amout the minimum to meet this. The taller lighter beams will need ALOT of lateral bracing to prevent twist and flopping over.

I say a pair of rails are no good for this project. 20' span each rail would only be good for about 2500# of weight. But again, this is strictly taking the material shape and moment of inertia and assuming as if it were the same steel that I-beams are comprised of. I havent used rail for anything other than rail (not on a railroad, but for things like gantry cranes). So I cannot speak to the other concerns that other people have mentioned
 

Tractor & Equipment Auctions

Adams Tender Trailer (A35780)
Adams Tender...
L Shaped Fuel Tank (A35719)
L Shaped Fuel Tank...
Club Car Golf Cart, (A35430)
Club Car Golf...
Powerscreen 26' Sand Screw (A36337)
Powerscreen 26'...
Honda HRAR14 Walk Behind Self Propelled Mower (A36602)
Honda HRAR14 Walk...
SeaRay 21ft Sport Boat, (A35430)
SeaRay 21ft Sport...
 
Top