Why aren't locomotives made aerodynamic?

[Anonymous]

And don't tell me by the shape of them they are because then I'll have that feeling you have a bridge to sell me. All locos, even to this day, are "boxy" in appearance. That must present a high coefficiency despite all the inertia (AKA push load) of rolling stock. Things could be better.

[Anonymous]

If you're looking at the point deflecting the air and all else behind point collecting a coefficient drag, well I thought that problem was once solved sometime during the 1980s with the installation of fans on certain rail cars facing upwards countering any fluid opposition flowing into the openings throughout the system of cars. From that point (from what I see), what's left is what's taking point.

There are better bearings than what is currently being used on railcars. What's still happening today leaves me asking, "Who's the real McCoy?" Sad.

[M636C]

EMD made a half hearted attempt to improve the front end of the GP60 and GP59 demonstrators by rounding the hood edges and putting a vee-front on the cab, which was a reflection of the styling changes on contemporary road trucks.

The SD70 ACe and SD70M-2 show no such influences!

Peter

[Overmod]

Huh?

The longitudinal air resistance of any substantial train due to aerodynamic drag on the power is not a major proportion of train resistance at typical track speeds. You are correct in thinking that the major component of train resistance is at the cars, not at the locomotives. The situation is, of course, progressively different as speed advances above about 85 to 90 mph, with nose streamlining becoming essential, but you should also consider that the built-up regions of high pressure ahead of the locomotive function quite effectively as a streamlined 'nose cone' and very little actual reshaping or vanes are required to control this quite effectively. If you don't believe this, ask yourself why a pickup with full tailgate gets better mileage than the same model with one of those stupid "flow-through" panels...

Meanwhile -- we're not in the cab-and-booster era any more, and unlikely to return to it in freight service... ask the railroaders on the list why if you haven't read the previous threads on the general subject. If you have three identical locomotives in the consist... how do you streamline them all effectively? Just pointing the nose isn't going to help too much. There isn't much involved in putting a Genesis cab on a Dash-9 style unit; ask yourself why even with fuel at current levels, no railroad is doing this. Yeah, I know, it's godless capitalism... but capitalism is a mighty good determinant of action when money's at stake... and saving money is really what your take on streamlining is implicitly about.

Fans blowing air into the gaps between cars would likely consume far more power than would be used to overcome the drag attributable to the gaps -- completely aside from the capital cost of providing them. (And what would you propose for the gaps where there are empties?) I'd like to see the reference for this idea.

A somewhat 'better' solution is inflatable diaphragms at the car ends... the idea being to give reasonable flow stabilization past the gaps, not provide perfect 'streamlining'. It is also possible to use active or passive vanes or airfoils to control some of this. My opinion is that it's the instabilities, not the 'air resistance' per se, that causes the major problems at freight speeds. The cost and operational complexities of these systems generally precludes their adoption in routine service -- just not enough saving to justify the hassles that the crews have to go through to make the stuff work right, every time, and keep it all in proper operating condition. (I'd like to think that it would stay perfect, but Murphy and Finagle have resolved otherwise...)

Likewise, the drag attributable to crosswinds dwarfs that of longitudinal movement, particularly on TOFC (with high drag around the undercarriage and due to the higher profiles and longer gaps) and COFC with ribbed-sided containers. Laymen often seem to think that the only 'wind' on a train is that which comes directly from the front, and that crosswinds short of those violent enough to derail cars do nothing more to train resistance than 'make the cars sway'. One solution used in Europe was to increase tumblehome on the vehicle sides -- something that doesn't 'package' well in the world of ship containers!

Regarding the better bearings: I get the impression that you're looking at some other definition of 'better' than applies in the railroad industry. You do understand why magnetic bearings aren't used on boxcars, or even intermodal trains, don't you? Even in the 1990s, Timken was building bearings with low friction and sealed maintainability past the wear limits on the wheels -- better than that is essentially pointless. If you look at the recent research into top-of-rail lubrication, you'll note that this produces increased running efficiency higher than that which would result from 'perfect' lubrication in the bearings (i.e. no component of rolling resistance attributable to bearings) -- some proof, I think, that very little additional efficiency is to be obtained from "better" bearings of any design; there had better be a minimum 500.000-mile life without maintenance or external power on your 'better bearing' for it to be even "as good" as what current technology provides...

There are MUCH better things to be redesigned on conventional freight railcars than bearings. Start with continuous wheel profile turning (and precise pair sizing), field hard-coating of wheel treads, better brake composition and actuation mechanisms, and multiaxis damping (particularly including yaw damping, which must be proportionally greater for high rates, among other things). Then see if there's an economic justification to magic-wear-rate grinding, better 'tuning' of transitions, teaching crews how to actually line and surface transition spirals with existing equipment, etc. Make stick flange lubricators and top-of-rail systems ubiquitous... if they pay. All these things have, imho, a greater influence on train operations than aerodynamic drag. And we haven't done more than scratch the surface on how to eliminate unnecessary stops and slow orders, even one of which wipes out the whole theoretical gain from locomotive streamlining...

I have very little doubt that bean-counting railroad management would embrace locomotive streamlining if it paid. I concur that (imho) it's a little shortsighted for GM to embrace so aggressively 'unstreamlined' an approach as the SD70M-2, particularly considering what these locomotives cost, but I'm also not privy to construction economics, and have learned not to second-guess people or judge situations in a business without finding out the facts and context beforehand.

Whether we like it or not -- and in quite a few ways I don't -- railroads exist to make money, not maximize efficiencies. This is particularly hard for me, at times, because I have a love of technology, effective and elegant design, high speed, DFM, etc., as well as a certain romance for that part of railroading that runs trains fast. It's quite logical to burn more fuel to save money... if you have run your numbers correctly and are actually making money on the bottom line, and aren't Penn-Centraling your railroad somehow by deferring critical things (like maintenance) until the situation goes nonlinear. My opinion is that modern railroad management are not a collective pack of blind fools, and are, in fact, quite cognizant of fuel burn and desirous of reducing it.

As an exercise, I'd like to see a full lifecycle costing of streamlining as applied to locomotives -- fab cost, maintenance and crash-resistance implications, cooling, wake-turbulence analysis, etc., balanced by the savings attributable to the practice. (If you like, include the goodwill attributable to the better appearance... that was, after all, a principal justification for streamlining on both steam and diesel locomotives in the past!! ;-})

[kevarc]

AS stated above, thefrontal area of the engine really makes little difference in wind resistence. The makeup of the train is the key.

A train of covered hoppers of will have less overalll resistence than a mixed freight. The worst are TOFC, containers, and empty coal/hopper cars.

A consist of empty coal cars will have approx. 40% higher resistence than a loaded on. The wind gets in the empty hopper and just kills things.

[Sterling1]

It's usually the price of making them aerodynamic, it costs more.
EMD tried it with aerodynamic version of the GP59 and GP60 demos with a V-shaped front end of the cab and rounded cab and nose corners Nevertheless, the price made it impossible to repeat the extras.
Anyone who want to correct me go ahead, all of us are still learning . . .

[Anonymous]

Wow! With all the hot air rushing by me here I thought I was running really fast for a minute there...lol...

Unless you are talking about a TV train or maybe MLs the speeds you see in freight service rarely get beyond 50mph. Even on the road there are plenty of grades, curves and other temporary and permanent speed restrictions. Don't get me wrong, I'd love to see performance improved, but putting fans on cars? It is hard enough to get people to spend the money on things that would have much more tangible benefits such as equipping each car with electronic air brakes. Besides, the designs of freight locomotives need to take into account their common uses such as switching. All those steps and walkways don't make for a terribly aerodynamic shape but, have you ever tried to switch with a F unit?? It can be done, but it isn't fun.

So, Chessking, how's your twin brother Terry doing these days???

FOFLMAO...

LC

[Anonymous]

I think you'll find that trains that travel at faster speeds will be more prone to being aerodynamically designed.

Acela and Bullet Trains being a good example.

[edblysard]

No,
Seriously jim(chessking)
Do you know who the real McCoy is, and what he invented?

Besides, if you already had the knowledge, why did you ask the question?

Trolling, or just cutting bait?


Ed

[Anonymous]

Well, I could do what others do: Go find the answer somewhere online, copy and paste to here, then shine. But I'm not going to do this. I'm going to attempt this one just on what I know. So here it goes ... laugh as you may.

Wasn't McCoy a railroad worker who invented some thingamajig allowing constant lubrication to the wheel bearings and other moving mechanical parts while the train is moving? or something like that.

[Anonymous]

QUOTE: Originally posted by Limitedclear



So, Chessking, how's your twin brother Terry doing these days???

FOFLMAO...

LC

The fans on the rail cars was a catch. Just wanted to see if someone would try to BS through it like ," Oh yeah I know all about those fans ... it was 1982 ... blah blah blah ...". But on a serious note, to take shots at someone who's deceased was rather distasteful and disrespectful. Some here might take offense.

[dharmon]

Well if the prince of pawns is a part of the troll tribe, he learned how to spell and punctuate at least.

[Anonymous]

I'm not a troll. If you want to believe this, go right ahead. I'm not here to win your approval. And as for spelling, I am a very good speler ... Ooops.

[dharmon]

QUOTE: Originally posted by chessking

QUOTE: Originally posted by Limitedclear



So, Chessking, how's your twin brother Terry doing these days???

FOFLMAO...

LC

The fans on the rail cars was a catch. Just wanted to see if someone would try to BS through it like ," Oh yeah I know all about those fans ... it was 1982 ... blah blah blah ...". But on a serious note, to take shots at someone who's deceased was rather distasteful and disrespectful. Some here might take offense.

...and how would we know that? Sounds like insider information to me.......

[Anonymous]

Someone mentioned it in here as the late Terry C.

[kenneo]

Limited Clear, Ed, Mark ---

My wife nearly had to call the EMT's to the house! I got to laughing so hard about the installation of fans to reduce drag that I started choking and she couldn't get me stopped.

Ed, the only thing I troll for is Salmon, and for that I use a boat, pole, bait, state Mariners Certificate and a Fishing License. Our "friend" appears to troll without a boat, license and has yet to mention phishing or what he uses to phish.

I'm going to have to not read chessking anymore. My ribs are going to hurt for a week and may well break the next time he pulls one of those stunts.

[dharmon]

QUOTE: Originally posted by kenneo

Limited Clear, Ed, Mark ---

My wife nearly had to call the EMT's to the house! I got to laughing so hard about the installation of fans to reduce drag that I started choking and she couldn't get me stopped.

Ed, the only thing I troll for is Salmon, and for that I use a boat, pole, bait, state Mariners Certificate and a Fishing License. Our "friend" appears to troll without a boat, license and has yet to mention phishing or what he uses to phish.

I'm going to have to not read chessking anymore. My ribs are going to hurt for a week and may well break the next time he pulls one of those stunts.

You mean those fans on top of locomotives are for something else? Gosh dernit...I better go back to the internet and start looking stuff up.

[Anonymous]

I dont think areodynamics is going to benefit the train. If the Japanese Bullet or Maglev needs it great! But your regular hogger with a stack of 100 unruly cars rocking along really has other horsepower concerns than areodynamics. I would at least try to design a engine to use the drag to assist the fans in cooling, removal of heat, cooling the traction motors, the dynamic brakes etc.

There is alot of drag on the engine, I see it as potential "RAM AIR" Cooling.

[Anonymous]

While you're at it stop by the DINA and get a cup of coffee. And dharmon .. No, a centerbeam is not a new brand of bourbon. And No, an autorack is not your daddy's pickup with deer antlers fastened to the hood. And a grade crossing has nothing to do with you taking 3 years of kindergarden before crossing over to the first grade. And by no means are you correct when you thought tractive effort had something to do with excremental fortitude.

[arbfbe]

There is more drag on rib side cars, open top hoppers, cars with open doors, bulkhead flat cars and spaces between double stack intermodal cars than from the front, sides and tops of the locomotives. If someone tried to sell locomotive streamlining as a serious fuel saving measure they should be laughed out of the office. I know from experience that a two or three unit loaded grain train will make better time than a two or three unit empty coal train in calm air and much better time if there is any wind blowing at all.

[081440]

Just think of the maintenance costs of taking all that aerodznamic stuff off and on. Besides with the weight they are pulling that air resistance is miniscule.

[M636C]

But why post something that isn't true just to catch someone out?

I did think the "fans" comment was odd, but I've seen equally odd things tried by people who didn't understand the problem.

In fact, the Hunter Valley coal trains in NSW, Australia, have very aerodynamic coal hoppers, geneally called "batwings" from their shape. They have curved sides with a very narrow top opening, just wide enough for the loadout hoppers, and are coupled close together (in fact bar coupled in rakes of seven or eight depending on the type).

This greatly reduces the aerodynamic drag, but the real purpose is to reduce the loss of coal dust by the reduction in aerodynamic turbulence - Not so much because the load is lost, but to make the trains more environmentally (and neighbour) friendly.

I thought the bearing comment was the really unlikely point!

Peter

[ericsp]

QUOTE: Originally posted by chessking

Wasn't McCoy a railroad worker who invented some thingamajig allowing constant lubrication to the wheel bearings and other moving mechanical parts while the train is moving? or something like that.

That sounds like that would be incredibily expensive with only small benefits.

[ericsp]

LC, at least I know I am not the only one getting suspecious.

[Anonymous]

Ok Ok, I give. What's McCoy?

[kevarc]

Ah, so this forum does have a court jester!

[Anonymous]

Congrats on the recent promotion kevarc.

[edblysard]

You know,
My 17 year old daughter seems to do the same thing...
Keeps asking the same question, in various guises, in an attempt to get the answer she was looking for, so she can make the grand, self serving statement, or offer the same, self serving excuse.

With the same results, of course.
Its hard to play dumb when your not.

The very fact that in the original question included the words push load and coefficent should warn all that the person asking the question already knows the answer, and is just looking for a sucker to provide the "wrong" answer, so the poster can offer the "true" answer....

And Chessking?

Maybe checkers...

And the answer here should be the same one I offer my daughter...
No this time, and no the next time too!

Ed[:D]

[M636C]

There was a French plain bearing axlebox called "Athermos" which was reasonably well sealed and had an oil reservoir at the outer end of the axle with a "paddle wheel" bolted to the axle end inside a larger diameter end cap. This gave continuous oil lubrication without using open reservoirs and cotton waste, which could cause problems with contamination.

These appeared on a number of European vehicles and to exports to Francophone Africa, in particular.

There were quite complex lubrication systems on steam locomotives, the "Detroit" sight feed system being familiar to me. The Germans had an extraordinary mechanical lubrication system on their speed record locomotives of class 05, which can be seen on the locomotive preserved at Nuremberg. This is the fastest steam locomotive in the world, if remaing operational at the end of the record run is a criterion! The British "Mallard" had to be taken off the train at the first station after its "record" run after the central cylinder big end bearing failed!

But the name Mc Coy does not come to mind in this context!

Peter

[Anonymous]

Awww edblysard ... if you say it again, I just might cry.