Western Railroad Discussion > UP Arrowhead Wedge Container

Seeing Grandgolds images of the UP Arrowhead Wedge container,I was wandering if this will offer a fuel savings taking in consideration it replaces a revenue producing container of at least $900 dollars so with price fuel at $2.00 per gallon it would have to save 450 gallons of fuel plus the cost to build the Wedge.

It might be they are going to develop the Wedge to attach to a 40ft revenue producing container

In the trucking industry today with all the skirting wheel covers tail reflector they are seeing a Six percent increase in mileage

What do you think?

Posted from iPhone



Edited 1 time(s). Last edit at 04/16/17 17:29 by mearsksealand.

> Seeing Grandgolds images of the UP Arrowhead Wedge container,I was wandering if this will offer a
> fuel savings taking in consideration it replaces a revenue producing container of at least $900
> dollars so with price fuel at $2.00 per gallon it would have to save 450 gallons of fuel plus the
> cost to build the Wedge.

> What do you think?

Hello,

Briefly, I don't think the key issue is the replacement of another container.  That other container will just move in another position in the train so UP will earn that money either way.  

What I'm very skeptical of is the results of the study that says the Arrowedges provide cost benefits overall simply because of their aerodynamic efficiency.  Based upon the info they've released publicly, it doesn't seem like they took everything into consideration before pulling the trigger on them: 

Costs:
- design, testing
- cost to purchase (the $ to buy them and finance them)
- maintenance, repairs while they're operating
- lift on/off costs at the terminals,
- storage, handling costs at the terminals,
- additional aero. drag they create while on the trains
- extra fuel needed to move the weight of the Arrowedges   

Benefits:
- fuel savings from reduced aero. drag on first few containers of the train.


My gut feeling is, if they looked carefully at the actual costs and benefits over time, the units will provide little or no net benefit.  The video and info that UP has provided to the public make it seem that they've overlooked several basic aero. issues (here's a video):

http://www.up.com/aboutup/community/inside_track/arrowedge-redesign-04-27-2016.htm

 - the video mentions testing of the train at "70-100 mph" wind speeds.  You might occasionally get wind speeds that high but a practical average is probably more like 40-75 mph.  If tested at 70-100 in the wind tunnel they'll get results that look much better than what you'll get in the real world.  
- winds are only rarely straight-on as they are in the wind tunnel (airflow perfectly aligned with the train).  In the real world winds are almost always hitting a some angle, such as a 30 degree headwind.  The more the wind hits from the side or rear, the less benefit you get from the Wedge.
- It doesn't look like they factored in the impact that exhaust from the stacks and radiator fans has on airflow over the locomotives.  With simple locomotive models in a wind tunnel, there's no exhaust and air flows relatively cleanly over the locomotives and onto the first container.   In the real world, the effect of the exhaust air emitted from several locomotives working hard is to lift the airflow as it passes over the locomotives, so air hits the first container much less "cleanly" than in a wind tunnel.
- another factor is that the exhaust air from the locomotives has been accelerated - it's moving at the same speed as the train when it's discharged.  So that stream of exhaust air that's hitting the first container on a moving train isn't hitting it at full speed, but at some lower speed.  
- exhaust air is also very hot meaing that it's much less dense than the ambient air that they're using in the tunnel.  That flow of hot air hitting the 1st container in the real world causes much less drag than the air used in a static, "cold" wind-tunnel test.

Each of those issues, if they didn't properly factor them in, would reduce the benefits of an Arrowedge on a stack train.  I'd love to see their actual test results to see if they considered the issues or not.  If not, I think they probably overestimated the benefits of the devices, perhaps to the point where using them isn't worth the effort.


Take care,

Mark

  

I am very sure UP looked at all that before they put it into effect.

UP lets Ed Dickens screw up so bad it costs the company millions so the money for the Arrowhead Wedge is no biggie for them

You loose the revenue for the slot it is not replaced by another container loaded on the train.

Each stack car carries either two 40 ft or 53ft two twenty foot on bottom topped with 40ft or 53 ft each slot is revenue

Dale Smith

 

mearsksealand Wrote:
-------------------------------------------------------
> You loose the revenue for the slot it is not
> replaced by another container loaded on the
> train.
>
> Each stack car carries either two 40 ft or 53ft
> two twenty foot on bottom topped with 40ft or 53
> ft each slot is revenue
>
> Dale Smith
>
>  

Well if you save enough fuel to offset the revenue loss, it's a moot point.
Has anybody seen any kind of numbers on how much fuel these things are supposed to save?

mearsksealand Wrote:
-------------------------------------------------------
> You loose the revenue for the slot it is not
> replaced by another container loaded on the
> train.
>
> Each stack car carries either two 40 ft or 53ft
> two twenty foot on bottom topped with 40ft or 53
> ft each slot is revenue
>


Hello Dale,

That's true in theory, but container trains are almost never fully loaded (all slots, all cars). In nearly all cases, the container displaced from the front/top spot by an Arrowedge just loads somewhere else on the same train, in a slot that would have been empty. In those rare cases when a train is full, the displaced container would just move on another train later - no lost revenue to UP either way. Same principle as overbooking of airline passengers, except you don't need to call in the police to drag a disobedient container off of a train ;-)

Take care,

Mark

PHall Wrote:
-------------------------------------------------------
> mearsksealand Wrote:
> --------------------------------------------------
> -----
> > You loose the revenue for the slot it is not
> > replaced by another container loaded on the
> > train.
> >
> > Each stack car carries either two 40 ft or 53ft
> > two twenty foot on bottom topped with 40ft or
> 53
> > ft each slot is revenue
> >
> > Dale Smith
> >
> >  
>
> Well if you save enough fuel to offset the revenue
> loss, it's a moot point.
> Has anybody seen any kind of numbers on how much
> fuel these things are supposed to save?

The only conclusion I was able to deduce from the BYU-designed ArroWedge 2.0 is that the aerodynamics is no worse than the more complicated ArroWedge 1.0. That's what the wind tunnel test was about. Only tangible benefit I see is that it's probably cheaper to manufacture.

If UP wants to really measure the fuel savings from ANY ArroWedge device, they need to build a test train with strictly-controlled parameters. It needs to travel back and forth on the same territory. They also need to take into account how different engineers run trains differently, so they may need to designate a group of test engineers where experiments can be repeated with reasonable accuracy. I could go on, but technical people should know what I'm trying to get at.

I don't think UP's PR department is set up to do this sort of thing. Hopefully, the BYU students have better things to do than to work for an organization that makes decisions that often defy logic. :-)

I'm just proud that UP and in fact all railroads are willing to experiment and innovate. If they did not, we would still have steam engines, jointed rail, 40 ton wooden boxcars, and the industry would be even more outmoded.

Norm

Norman Orfall
Helendale, CA
TIOGA PASS, a private railcar