Why don’t the freight locomotives have the same aero look that the passenger loco’s have? Wouldn’t that help fuel efficiency for the freight locos?
Simply because it makes maintenance much harder and more expensive. Carbody style locomotives are much harder to maintain and need the prime mover lifted out of the carbody for repairs that hood units can have by simply opening the doors. This is why railroads changed from FAs and F7s to RS11s and GP7s. Fuel efficiency also is not critical for many types of service, such as unit trains, so the penalty is not as severe as it may appear.
The air drag of the train is way more than the drag of the engine. Plus most freight engines spend most of their lives at less than 40 mph so drag is not a big factor at slower speeds.
amar711:
Cool topic!
Hey, you can snap your fingers and oco becomes loco … and topic title distractions can disappear! Just be signed in and hit the “Edit” button … and the magic can be yours …
Back to your topic itself … I heard years ago EMD designers made the GP so ugly no one would want it in town, but out on the mainline between towns. Kind of backfired, as the Geep became everyone’s favorite.
Best,
K.P.
Unless you build a cowl design like the FP45 or the F40PH, a lot of extra expense is involved in fabricating either an Alco/GE flatnose or EMD bulldog nose.
Freight locomotives rarely spend their days just running from origin to destination. In the loose car network the is work (pick ups, set offs, switching) do be done as their trains move from origin to destination. In the bulk commodity world (coal, grain, ore, oil), where engines may run from origin to destination, speed is not a consideration - the name of the game is moving the tonnage at the lowest overall cost to the carrier.
Back in the 1980’s, EMD did some wind tunnel testing and came out with a cab that was more aeordynamic.
http://trains-and-locomotives.wikia.com/wiki/EMD_GP60
It turned out to be more trouble than it was worth - that is, the extra cost to manufacture and maintain was more than the fuel it could save.
The aero drag on a freight train isn’t so much defined by the shape of the nose or locomotive carbody as it is by that caused by the gap between cars.
The old cab locomotives (F7, E6, E7) were designed back in the era when streamlining was used as a marketing tool for passenger trains and the locomotives had to match. Originally had nothing to do with windflow…only appearance and convincing the public of speed via outside appearance of the trainset. A good portion of the interior design was in the art deco style to convince the passengers of modernity of the trainset.
So that was the original intent there, IMHO. Some of that still exists I’m sure with the HSR train sets among various countries (Especially their elongated nose design).
If you look at HSR trainsets, the wind drag is reduced mostly by the full-width diaphragms between cars (also makes passage between cars much easier) and only slightly by the tapered nose and ends.
Whatever happened to that recent U.P. concept of using the big wedge at the head end of a train, behind the engines, to reduce wind resistance?
Seems someone forgot about overhead clearances. It got smunched.
As has been noted, the resistance is not at the head of the train, it’s in the gaps between the cars.
Unfortunately, trying to put diaphrams (or such devices) between the containers in a stack train would be far more trouble than it’s worth…
Why was U.P. seeking to reduce air resistance by streamlining the front of the first car in the train?
Everyone needs a hobby.
Experimentation. Locomotive heights are about 16.5 feet. Double stacks are 20 foot 2 inches. The difference is approximately 3 feet 9 inches of a aerodynamic ‘brick wall’ after the air passes over the locomotives. I have no idea if UP found this successful enough to put into ‘production’.
In addition, a full carbody essentially kills bidirectional operation. With a hood design, locomotives can be operated at speed long hood forward. With the radiators of newer locomotives it isn’t fun, but it is doable.
Wide body freight locomotives, at least on my carrier, for the most part do not have ditch lights on the long hood end; as such there are restrictions that apply at road crossings at grade and they are not used in bidirectional service as leaders.
NS, CN and IAIS still operate their widecabs long hood forward on occasion and have installed rear ditch lights. I don’t think anyone else has.
Earlier road switchers such as the EMD Dash-2 line had the same advantages, while carbody locomotives usually require a crewmember to stand at the rear of the unit and look out when operating with carbody in front.
Here is an article describing the U.P. “Arrowedge” as well as other aerodynamic applications.