Hi there!
The small shortline railway that serves my town currently has a 220,000 lb weight limit and I'm curious what all is involved in upgrading the track to 263,000 or 286,000 lbs. Is it just heavier rail and reinforcing or replacing bridges or does it require rebuilding the whole roadbed? There's no major bridges on the line and I've always wondered why they didn't upgrade it for heavier cars.
Thanks in advance for all replies!
Perhaps they do not foresee a need and choose not to spend the $$$. They know what their customers require.
Setting bridges aside, the issues will be rail weight and age, ballast type and condition, and tie condition.
My guess is that the customer can live with 220,000# cars and the carrier sees not enough benefit to spend the money. This is particularly true if there is one customer and they are economically insecure.
Mac
And a big part of this will be each customer's 'last mile' of siding to their facility for loading.
In some cases, it might be possible for the railroad to construct a bulk unloading facility for multiple clients, like the one for covered hoppers in Erie, PA, which provides truck access (probably on a gravel apron) to a strengthened set-out track which can then be regularly switched. The facility there is not fenced or gated, but any level of cost-effective access security or monitoring could be provided.
(1) What do you consider a major bridge? In a railroader's world, anything that carries water is considered as a "bridge' (including drainage pipes and culverts)...All it takes is one small span in a key place to control the rating of an entire line.
(2) You can raise the weight limits for a while. The number of cycles will determine how long that will last. Too many cycles and game over.
(3) Most independent shortlines can't afford an engineer (bridge, signal or track)...That being said, the mandatory FRA bridge rating and bridge program rules of the last ten years may have forced the "we run trains" operating bubbas to wake up and understand what they have been running on all these years after a consultant was brought in to keep the shortline in FRA compliance.
(4). A switch to welded rail along with an overdue tie program can do wonders. Replacing tired OTM (especially joint bars) and a little surfacing does great things when you add a little cascaded-down secondhand rail (probably heavier than what was there to start with*)...The industry is starting to see issues with where to place some of that secondhand welded rail that is still servicable, but should not be in heavy haul high-tonnage use. (not enough proper sized SH tie plates, etc)
Light weight rail is not worth flashbutt welding, especially if it is end-battered (badly needing to be cropped on the ends) and near the end of its life. (with many shortlines, already beyond that point ...JoeK saw that)
...and then there is that customer, the clueless one, that won't or can't maintain the track at the industry at the end of the line - even though most of the time that is their responsibilty. Far too many of those to count. (Drives roadmasters and field engineers nuts) ... Anyone who reads AAR embargo notices sees that trend ("track conditions") is only getting worse.
mudchicken...and then there is that customer, the clueless one, that won't or can't maintain the track at the industry at the end of the line - even though most of the time that is their responsibilty. Far too many of those to count. (Drives roadmasters and field engineers nuts) ... Anyone who reads AAR embargo notices sees that trend ("track conditions") is only getting worse.
From my experience, it seems that customers, at least the small ones, tend to rely on the Carriers regular MofW personnel to do their track maintenance on a weekend/holiday cash basis. Needless to say these customers are doing everything on the cheap, cheap, cheap.
Larger customers will likely deal with railroad maintenance contractors who will likewise be granted the job on the cheap.
When I was working, I was keeping some statistics on track issues on my division. Some of the main line divisions had rail that was nearing the end of it main line heavy haul life. Once new rail was installed, the incidence of track issues on those territories decreased to almots nil. Rail does wear out - every axle that passes over it adds to the wear, especially when that axle has a loading approaching 40 tons per axle.
Never too old to have a happy childhood!
Many a foreman/roadmaster/track supervisor has had to deal with the rail customer that is angry about a track caused derailment that was due to failing track structure that has not been maintained (ever)...Gets worse when there is a landlord involved and there is a joint M&O agreement in place that the landlord or industry ignores. (Elkins Act be damned!)
Pig feathers start to fly when there is a "hot" railcar waiting on delivery or a car that needs to be pulled and the track department has spiked the switch o/s because the track is unsafe for any of several reasons (track condition, clearances, water, bad footing, bad vegetation issue, etc.) on the industry's side of the division of ownership. The shortline version of this can get really strange.
Welded rail explained
https://www.youtube.com/watch?v=zqmOSMAtadc
The simple fix for the image above is making rails out of Nitinol.
What's funny is that the two people I've learned the most about Nitinol were my oldest son and my cardiologist. FWIW, my oldest son is working on a PhD in ME with focus on materials science.
Most shortlines live on a hand to mouth existance ("shoestring operations with scary financing).
Unless there is some justification to improve track to handle increased tonnage, not gonna happen. 263K operation on existing track, roadbed and structures will do just fine with careful maintenance. Heavier tonnage will speed up the deterioration of the track, bridges, and roadbed ...but you can still run on it to a point. Upgrading to 286 or 315K ratings is not cheap.
Somebody hopefully is looking at existing trackage, tonnage and train frequency and the required FRA Bridge Maintenance Plan that is in effect for the line. (and is NOT one of the "we run trains" operating knuckleheads that are so prevelant in shortline management)
Erik_MagThe simple fix for the image above is making rails out of Nitinol.
You did see the mischief emoji, did you not????
As for forming nitinol rails, it's a simple matter of heating the rail up to 500ºC and then massaging it into shape, followed by cooling. (N.B. "simple matter" as in " just a simple matter of programming")
You did see the smile emoji, did you not?
I wonder if rail snakes can reach the necessary temperature for the necessary time. It is fun to imagine a rail-bending facility with a gantry a couple of acres in area, which bends the rails to precise top-down geometry depending on where they are to be installed and then anneals or whatever you call it the rails. Of course you then have to bend them straight again for the rail train, and then heat them in situ so they resume the desired curve...
Perhaps a part of Don's upcoming 'railroading in 2050' piece... ???
EuclidThere is no need for Nitinol.
I'm pretty sure that was a tongue-in-cheek suggestion...
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
tree68 Euclid There is no need for Nitinol. I'm pretty sure that was a tongue-in-cheek suggestion...
Euclid There is no need for Nitinol.
Pretty much had to get my tongue surgically removed from my cheek...
EuclidI realize that Nitinol was just tongue and cheek as a fantasy to solve the problem of expansion and contraction.
Of course, there are 'certain other drawbacks' to using Nitinol alloy in 136lb rail that is supposed to be field-welded... My point is that the seemingly impossible feat of restraining the rail so it cannot change length sufficiently to buckle or pull apart is not well understood because expansion and contraction of materials is commonly believed to be an irresistible force.It's only 'seemingly impossible' because the 'common belief' is wrong. Interestingly enough, there is a discussion in Machinery's Handbook of precisely how the cross-sectional area vs. density of a material changes when it is heated (or cooled) with constraint. Any real track engineer understands all this clearly as it was part of his education.
My point is that the seemingly impossible feat of restraining the rail so it cannot change length sufficiently to buckle or pull apart is not well understood because expansion and contraction of materials is commonly believed to be an irresistible force.
The use of Nitinol is one way to illustrate the solution concept. It shows that the common belief that expansion and contraction are unstoppable is true, but the overall object size can nevertheless be restrained as though steel rails were rubber.
The principal difficulty in conventional track is that (as a consequence of geometry) very small nominal changes in tangent length result in comparatively large changes in relieved arc displacement -- think of it as the 'reverse' of pushing sideways on a taut towline to exert higher force. If the track is composed of unconnected crossties, with only ballast holding them in position, it can be difficult to hold precise geometry beyond the extension (or contraction) of the rail steel by more than the nominal allowance chosen by setting the neutral temperature. Once one or more of the ties has started to shift, the stress as it relieves will tend to move more of them, and there may be resonance effects like those in a snapped string that lead to the kind of sinusoidal kink that produces good pictures in Trains.
A useful exercise for you is to look up the design of the Class 9 slab track that FRA tested a couple of decades ago, and work through how the stress from lengthened or reduced rails is transferred to, and accommodated by, the structure without changes in vertical (top-down) running geometry.
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