This morning I saw a UP container train westbound at Rochelle. It was on the track 1, so it could not have been destined for Global III. It had one of the Arrowedge devices on the first car.
I wasn’t counting, but the train had to be at least 150 cars. The vast majority were double stacks. However, at six or so places in the train, there was just one car that was single stack.
I am wondering that since the railroad finds the efficiency of the Arrowedge sufficient to surrender a revenue producing place on the train, would it also make sense to ship an empty container on any car that would otherwise be a single stack?
In my considered opinion, Arrowedge is a scam. The quartering drag between stacks is enormously greater than the reduction (not elimination) of the frontal resistance of the first container; there’s a reason long forebodies on locomotives weren’t and aren’t successful requirements for freight speeds. (If you were talking Super C speed and better, there begins to be an advantage for nonrevenue specially-handled streamlining … but I suspect you could get far better results out of something like Airtabs on the trailing container edges.
I don’t want to say Arrowedge is a sweetheart deal but I think there is some special, dare I say McKeen-like relationship there.
You have very astutely pointed out that empties for ‘better continuity’ might make sense, as any gap in the stack introduces most of the frontal resistance an Arrowedge device supposedly overcomes. I have not seen a calculation of the added train resistance due to container tare weight (which is surprisingly little) vs. the measured air resistance.
Yes, there have been schemes to fill the gap between units with something that is more ‘aerodynamic’, including one using special 20’ units on articulated mounts between ‘coupler’ ends of multiple-well units.
Anyway, a few days ago I saw on the Rochelle cam a case where the arrowedge contributed negatively to streamlining. Behind the locomotives was a single container with an arrowedge, but it was followed by about ten more single-stacks, then a bunch of doubles-stacks. If anything, the arrowedge should have been on the last single before the doubles, but then the cost of the extra time to move it would probably make it not worthwhile. By the way, I’m skeptical about the value of the thing, too. (Not that I’m qualified to judge, though.)
Perhaps the train was to get additional loads in those ‘empty slots’ before traveling a long distance, or at higher speed, or in windier areas.
Drag on the train is, of course, higher with an Arrowedge that does not have a container immediately behind it – same basic reasoning as for a bobtail with one of those roof deflectors. (But the additional drag is likely as minuscule compared to overall train resistance as the ‘streamlining’ advantage was in the first place.)
It might be interesting to see whether special spreaders or attention are needed to move an Arrowedge vs. a standard top-lock container. I think a smart designer would rig the thing with collapsible ‘legs’ in front that would be raised to engage a standard crane spreader frame. If not … Euclid! Here’s another chance to get a major patent improvement!
I am wondering that since the railroad finds the efficiency of the Arrowedge sufficient to surrender a revenue producing place on the train, would it also make sense to ship an empty container on any car that would otherwise be a single stack?
Something that I think you are forgetting here, is that the Railroad DOESN’T OWN the containers, so they would basically be asking to use someone else’s boxes for the sole purpose of reducing their fuel usage.
Add in the labor expense of loading and unloading the empty boxes, in the end is there really any savings at the end of the day doing it?
It may look reasonable at first glance, but it may not be worth the effort/expense for the POTENTIAL savings. I don’t know enough to evaluate the possible savings myself, but I do see another side to the equation.
Something I think you are forgetting here is that there is an enormous glut of used containers, and UP could easily acquire all the containers they might deem ‘needed’ for the purpose in any given lane, probably for less aggregate cost than one new Arrowedge. Treat them as being in dedicated service like barrier cars for hazmat service. [EDIT: see the construction of the new Arrowedge 3.0, actually built out of a modified 53’ container.]
But still, I think little practical gain to using empties for streamlining – I don’t have time or patience to set up computations to analyze, but someone here will.
At the speed most freight trains travel does any attempt at streamlining really make a difference?
I’m reminded of the streamlined steam locomotives of the pre-war era. I read as good as some of them looked it really was just for looks, the streamling had little or no effect of performance or economy.
There were two fundamental kinds of steam streamlining (a bit like good taste vs. tasting good). Some (the MILW A class, the British A4s, and the German 4-6-4s and streamlined tanks) were scientifically designed to aid in high speed (some combining lower drag with better smoke-lifting for visibility at speed). On the other hand, some – probably most – were little more than colorful period tin intended to give a modern appearance for marketing.
There was a middle ground - the Kantola streamlining for the Commodore Vanderbilt provided something like a gain of 400 usable HP at 85-90mph (there is a number in Staufer’s Thoroughbreds, but I don’t have access to it now). This is meaningful but not essential in the usual range of steam ‘express’ service in the United States. PRR conducted wind-tunnel testing on that wacky 3768 clown-with-a-dump-in-its-drawers scheme, and there’s probably some objective range of drag-reduction numbers there; I’d be interested to see the counterpart for the S1 (a more sophisticated and far higher-speed design).
The famous NYC Dreyfuss streamlining, on the other hand, was a pathetic thing as far as actual drag reduction went. I don’t have my Quadrant Press book on streamlined steam at hand, either, so I can’t work through the list, but it might also be remembered that many designs with fancy shrouds didn’t have the machinery to make actual speed where the drag reduction would matter. C&NW E4s, the ATSF Blue Goose, and just about anything south of the Mason-Dixon line probably come in that category, although I will listen to demonstrable counterproof. We should also remember that even though we call the streamlining ‘tin’ it w
It runs from page nos. 8 to 30 (23 pgs. net). Aside from the numerous pictures of that result and others, the photos at the bottom of pgs. 13, 19, and 22 may be of interest to those here.
RME - thanks for your insights and comments ! (some of which are over my head, but that’s OK) [bow]
Hey All, I heard somewhere that the arrowhead only really works for about the first ten or so cars back. Afterwhich, air flow returns to “normal” for such a train. So I dont think youd find much of a fuel savings from this thing. As another poster noted, it does sound like some kind of “an interesting relationship” is going on here between some company and who? EPA maybe? Or the bunny huggers? On some steamers though, there was SOME advantage to streamlining. (i.e. smoke ears on 844, streamlined casing on 611)
Remember seeing something about the arrowhead on a website of the school eng. kids that were doing some of the design work on it. Didnt seem to me to be much of an advantage in the real world though. Esp. if its only good for the first few cars. Just a few of my thoughts.
Such devices were used on a lot of locomotives - and other approaches were used for the same purpose (see ATSF’s stack extensions) - and that was to get the smoke a little higher over the locomotive/train. They really had little to do with streamlining, and probably actually caused drag.
Two things about this: (1) as I recall the ATSF stack extensions, they were for better drafting (more ideal ‘chimney’ proportions) where clearance permitted, with the option to retract when not; and (2) the purpose of the practical smoke deflectors turned out to be less “lifting” the smoke as aerodynamically moving it away from the sightlines from the cab past the boiler, with minimum ‘structure’ obstructing that view. The elephant ears and their reinforcement are very ‘thin’ seen from the cab, and the displacement and vortex generation is ‘just enough’ to roll the smoke and steam away from the view – where it goes after that, particularly with high-efficiency low-back-pressure front end designs, will be down around the train (but that will presumably be air-conditioned equipment for fast service…)
“Lifting” a plume of smoke is obviously not going to work too well, and result in substantial drag – as was unsurprisingly found by most of the people tinkering with ‘smoke lifters’ at the top and front of the smokebox area.
RME: I tried to google this and am still wondering, however reading between the lines I have an idea as to the meaning, but can you 'splain this …“McKeen-like relationship”…ref your post Wednesday, April 12, 2017 5:14 PM Thanks endmrw0426171219
A little ‘fast and loose’ and not scrupulous scholarship, but relatively easy to fact-check:
As I recall, some of the development of Arrowedge was done by people “connected” with the Union Pacific organization, as I recall was the case with McKeen and how he got his ‘foot in the door’ with Union Pacific and then had assistance with his further development. In a sense this might be an example of a ‘scientific engineering’ achievement that has benefited much more from ‘who they knew’ than from ‘what they knew’.
I was not trying to make any connection between Arrowedge and the ‘windsplitting’ streamlining on McKeen cars.
The ArroWedge Concept seemed to be around a lot several months back, when operating out of the K.C. area. Then it apparently wound up in Chicago,in April, and got interchanged(?) on a train to Milwaukee; it was ok til it hit the 35th St. Bridge there, and wound up [tdn] [oops] Apparently, not nearly as areodynamic when running backwards?
CN, CP and CSX all have MANY of their own containers.
When you look at a CN domestic intermodal train, 40-50% of the containers will be CN containers.
Also, if you look at an average CN intermodal train, doubles/empties/singles will be randomly spread all through the train in no logical order at all. They just don’t care.
I don’t think it is a matter of “they don’t care”, I think it is more a matter that it is not ecconomical to care… if there were some ecconomic reason to spend extra time (pronounce that, “money!”) to arrange the train in some particular order, they’d do it (they do when the train must be split at some intermediate terminal!).
I am surprised that they will take the time (pronounce that, “money!”) to be sure the lead container car has only one container on it, so that this ArroWedge device can be applied and that they take the time (pronounce that, “money!”) to put the thing on the lead car.
Loading stack trains isn’t a trivial exercise. Ideally, you’d have everything stacked and nothing empty. Here are some of the hurdles:
You need to spot the right cars for loading.
You need to minimize switching of empties in the terminal.
You need to know what boxes need to be loaded.
You need to know how many boxes are going where (blocking).
You need to set the loading tracks as few times as possible and make your cut-off for building the train.
You have to be sure you can cover all your work for the day. Can’t optimize for this train that’ll leave you hanging for the next.
If you can have a computer algorithm do the heavy lifting, then the terminal mgr just has to tweak the plan. NS paid a good bit for a process to optimize intemodal loading including “selling” it to terminal operations. It seems to have worked.
