It's been quiet on U.P.'s testing of its Arrowedge technology to reduce wind drag on doublestacks, which started a year ago September. At least I've been unable to find any updates on the U.P. website or elsewhere on Google.
Has anybody seen an Arrowedge in action lately?
Modeling BNSF and Milwaukee Road in SW Wisconsin
Wow! that route is cleared for double stacks so I wonder what happened..
http://trn.trains.com/news/news-wire/2014/03/experimental-arrowedge-container-receives-unexpected-durability-testing
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
The fuel savings are proably not that great all factors considered... maybe just enough to buy the crew a happy meal.
Ulrich The fuel savings are probably not that great all factors considered... maybe just enough to buy the crew a happy meal.
The fuel savings are probably not that great all factors considered... maybe just enough to buy the crew a happy meal.
Depends on how the thing is used. If it is only at the front and rear of the stack consist, I agree that the gains will be comparatively slight -- the great drag is due to the gaps between containers, particularly in a quartering wind.
Reading between the lines, this is a 'railroad' approach to providing the sort of deflector now used on many highway trucks -- where frontal (and tail) drag reduction is significant. Remains to be seen if this 'employee-suggested' technology actually does produce 'supersized' fuel savings (net of all the fun involved in placing and picking the things).
I still wonder if there is a place for something like Airtab-equipped strips ('locked' at top and bottom into the corner castings), if you have to have something aerodynamic applied at 'run time' that might make a positive difference to the important constituents of drag. My concern would be that the Airtab-generated vortices might destructively interfere with airflow over the gaps, rather than smooth it... who has firsthand experience?
[I have a hypothesis. The 'busted' Arrowedge in the Trains picture will have been on the tail of the train, and I suspect will not have been positively locked to the corner castings on the container underneath (probably relying on its mass to hold it down). Aerodynamics, perhaps in turbulent gusting, preferentially lifted the broad edge enough to contact the bridge structure...]
OvermodMy concern would be that the Airtab-generated vortices might destructively interfere with airflow over the gaps, rather than smooth it...
Shades of "Mythbusters!" Your question (a valid one) reminds me of the research they did regarding whether having the tailgate on a pickup up or down was better. One might think that having it down would introduce less drag, but it turned out that a small, horizontal vortex formed in the bed of the truck when the tailgate was up, greatly reducing drag.
I'd find it hard to believe that a railroad would introduce something like this based only on "we think it will work," but stranger things have been known to happen.
On the other hand, such an experiment might cause further research into how to best deal with the issue. Changing the distance between the containers (ie, changing the length of the cars) could make a difference, if an optimum distance is discovered.
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 ...reminds me of the research they did regarding whether having the tailgate on a pickup up or down was better. One might think that having it down would introduce less drag...
What I thought was the most interesting part of that was the research into whether a PARTIAL tailgate (with openings or louvers/slats) reduced the drag of a solid one. Turned out the perforated version (even with 'streamlined' openings) had MUCH more drag than closed, open, or removed. (And this could have been predicted pretty easily from first principles, although it definitely helped to have the 20/20 hindsight...).
Something else your story reminded me of, perhaps more ominously:
There was a story (I don't remember the source) about a WW1 aircraft design that was "improved" by having some of the reinforcing structure of the biplane wing either made or enclosed in an exaggerated "airfoil" shape (nominally to reduce the drag from wires). In flight, far from providing flow streamlining, this produced so much vortex over control surfaces that it made the aircraft physically unstable. I wonder if operating an Arrowedge 'backward' might be producing this kind of effect...
carnej1 Wow! that route is cleared for double stacks so I wonder what happened.. http://trn.trains.com/news/news-wire/2014/03/experimental-arrowedge-container-receives-unexpected-durability-testing
If you look at the damaged area..It is on the larger end of the container.. Normally, would that not be the ' trailing edge' ? of the airfoil container?
Looks to me like it might have been loaded backwards on the train? Possibly, it also was not 'locked down" completely? Thus allowing wind from the movement of the train to lift the large end of the wedge above the clerance required for the train? Bridges 1- Arrowedge Container 0
No savings from the Arrowedge that day!
The route is not cleared for Doublestacks, as the UP has no Intermodal terminals in Wisconsin or Minnesota, so there is no reason to spend the money. if the Arrowedge hadn't hit the bridge, the first can behind it would have been the one taking the damage. This was a routing mistake. Also the Arrowedge was designed by Mike Iden who has an Engineering Degree, and it was tested at the TTC near Pueblo, CO.
Also the Arrowedge was designed by Mike Iden who has an Engineering Degree, and it was tested at the TTC near Pueblo, CO.
beaulieuAlso the Arrowedge was designed by Mike Iden who has an Engineering Degree ...
Likely more important that he is the 'general director - car and locomotive engineering.' Here is an article about him from 2010.
He's had a patent application pending since 2010 for ... applying Airtabs or winglets to a standard cab to reduce some of the drag (the application is 20100326316 A1). It is instructive to read this, particularly the reasons he gives for the invention, and then to assess the amount of drag reduction the devices provide ... compared to, say, the quartering drag due to the intercontainer gaps on a fully loaded stack train. Bear in mind the speeds at which the equipped trains will be operating.
In my non-humble opinion, he's channeling Frederick U. Adams with a bit more nominal knowledge of vehicle streamlining techniques in other disciplines. The alarming thing is that none of this is particularly new, or was particularly new in 2010, (or in the 1960s with the streamlining chosen for the Metroliner designs); I think he is extrapolating from truck design (where small incremental economy gains in frontal/axial drag reduction can add up to potentially significant savings). We had a previous thread on this, with some of the usual suspects:
http://cs.trains.com/trn/f/111/t/220454.aspx?sort=ASC&pi332=2
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