Streamlined/shrouded steam question.

This thread begs the question: what railroad first streamlined their steam loco and what year was it done?

As David P. Morgan put it, streamlining did less for overcoming wind resistance, and more for overcoming customer resistance.

Perhaps the only utilitarian outcome of streamlining steam locomotives was raising exhaust above train ventilator level. maybe. Canadian National did extensive research on baffles in streamlining and elephant ear smoke lifters. No results have been published. Streamlined steam locomotives were no faster then their conventional contemporaries. If a locomotive was fast, it was built into the boiler and machinery, ala Milwaukee Road Hiawatha Hudsons. The close approximation, unstreamlined Santa Fe Hudsons were just as fast.

I think one must also consider the added weight of the streamlining and the increased amount of work needed when servicing them as well.

TM Terry posted:

This thread begs the question: what railroad first streamlined their steam loco and what year was it done?

I heard that it was the commodore Vanderbilt in 1934. The M10000 was the first streamliner in America. These are AFAIK.

Adams Windsplitter (B&O)    waaaay earlier....but not likely first.

Hey, it was a time to look fast and modern.  I doubt streamlined vacuum cleaners, trash cans or toasters performed any better that way either.  But they all looked great and are considered icons of a wonderfully aesthetic time. 

Streamling a steam locomotive does nothing to save on fuel or add speed to it.  Consider the weight of the locomotive and the cars it pulls.  Maybe speeds approaching 300 or 400 mph would make a difference if the entire train were streamlined down to the last rivet.  Of course rivets would not be used as they would create wind resistance......LOL   

The train would have to be light weight and streamlined at the same time.  Something that 1930s designers were doing with trains like the M10000 or the Zephyr.  

I'm not a physics whiz, just using a bit of common sense.  

Short answer...yes.

  "For his senior thesis in mechanical engineering at Cleveland’s Case School of Applied Science (Now Case Western University), undergraduate Norman F Zapf chose to test the feasibility of streamlining a 4-6-4 Hudson type engine. Zapf was familiar with Tietjen’s work at Westinghouse and with tests underway at Canada’s National Research Laboratories, where J.J. Green had, since 1931, been applying drag-reducing shells to steam engines.

  Zapf concluded from wind-tunnel test on scale models (with and without shrouds) that a typical top passenger-train speed of 75 miles per hour, with streamlining reduced drag by 91 percent; with crosswind effects the results were even better. By his calculations, a standard steam engine would expend 350 horsepower more than a streamlined locomotive with both operating at top speed, and his graphs showed that streamlining offered some power savings even below 50 mph. The model shroud was altered to facilitate maintenance on the running gear.

  Nearly all of Zapf’s suggestions were incorporated in America’s first streamlined steam engine, the Commodore Vanderbilt, which rolled out of the New York Central’s Albany shops in December of 1934. A three-year-old engine had been given a black zephyr-like shroud from which only the handrails protruded. A trough along the top channeled smoke up and over the cab. Preliminary tests indicated that in the 70 to 110 range, streamlining would effect a 2.5 to 12 percent increase in pulling capacity over standard engines. The Commodore Vanderbilt was quickly assigned to one section of the prestigious 20^th Century Limited operating between New York and Chicago."

From The Streamlined Decade – Bush – pp 69-70

Thank you Robert.
For those who happen to have a copy of "The Steam Locomotive" by Robert P. Johnson, M.E. of Baldwin Locomotive fame, you might want to read Chapter XXIV - Streamlined and Light Weight Trains....pg. 419. I'll let you do the reading.

Robert S. Butler posted:

Short answer...yes.

... Preliminary tests indicated that in the 70 to 110 range, streamlining would effect a 2.5 to 12 percent increase in pulling capacity over standard engines ... 

From The Streamlined Decade – Bush – pp 69-70

That sounds about right, Thanks Much for the low-down.

I can't see it, Robert.  I'm sticking with my mass and weight theory.  A scale model in a wind tunnel is not the same as the real deal.  

Cars and trucks I can see as benefitting from streamlining because their mass and weight ratio to the passing air makes sense to me.  Steam locomotives, streamlined or not, are just too massive and heavy to cause a difference.  

  Ok Dan, fair enough.  However, the last paragraph does indicate tests were run on the real thing and there was a measure of pulling capacity increase between 2.5 and 12%. 

  I think something else to keep in mind is that the Vanderbilt study and the measurements on the real thing are, as far as I know, the only tests run on performance differences of locomotives in actual service.  A read of the rest of the book The Streamline Decade and books such as The Steamliners by Holland, Loewy's book Never Leave Well Enough Alone, or  Kuhler's book My Iron Journey: An Autobiography of Steam and Steel,  strongly suggest Mark S's quote of David Morgan to be the point of most of the streamlining effort - the period was, after all, the time of the art deco movement which impacted the styling of products of all types.

Dan Padova posted:

I can't see it, Robert.  I'm sticking with my mass and weight theory.  A scale model in a wind tunnel is not the same as the real deal.  

Cars and trucks I can see as benefitting from streamlining because their mass and weight ratio to the passing air makes sense to me.  Steam locomotives, streamlined or not, are just too massive and heavy to cause a difference.  

 

Dan,
Let me give this real life happening as an extreme example of how much wind resistance can effect a train. Take a 100 car empty hopper train (a measly 3100 tons), add three GE Dash 9 locomotives (rated at 2900 tons per engine on max. 1.8% grade) all on line in number 8 notch on level ground. Now add in a 30 mph quartering headwind. This train would not make it up to the 50 mph speed limit. In fact, it would only do 40 mph on the straight and level. Double in fact, no braking effort was needed to slow the train down for a 30 mph curve after shutting the throttle off 3/4 mile from the curve.

A week later, 110 car empty hopper train (a bit more tonnage than the previous train), Two, I said TWO Dash nine locomotives (that is one whole loco less than before) on line, exact same stretch of track. There was no problem getting the train up to the 50 mph speed limit and after that was attained the throttle was reduced in order to maintain 50 mph. Shutting the throttle off in order to slow down for the 30 mph curve and used full dynamic brake to slow train down in time.

Now, you can believe whatever you want. If you still think wind resistance doesn't effect a train, I can't help you. If you still think streamlining doesn't help a locomotive cut through the wind, even by a much narrower factor than my example above, then I can't help you. If Baldwin's Robert Johnson thinks a chapter of his book needs to be dedicated to streamlining, I would say there was probably something to it! Heck, he didn't have to write a chapter to convince me. As Pee Wee so eloquently said..."I don't have to watch it, I lived it!"

I hope the next thing I don't see on this forum is that curved track doesn't create drag on a train.

Dan Padova posted:

I'm sticking with my mass and weight theory.  

Cars and trucks I can see as benefitting from streamlining because their mass and weight ratio to the passing air makes sense to me.  Steam locomotives, streamlined or not, are just too massive and heavy to cause a difference.  

 

What does "mass" have anything to do with a streamlined profile and wind resistance? A locomotive could be made out of lead or aluminum, and the wind wouldn't know the difference.

Well the streamlined German Class 05 4-6-4 locomotives held the world's speed record for years. The reports say that a streamlined Class 05 could reduce power by 20 percent hauling a train at 93 mph compared to a non-streamlined Class 05 locomotive.

The third term of the Davis Locomotive Resistance equation is wind resistance, and this resistance increases as the SQUARE of the speed. So, yes, wind resistance is a factor in anything that moves on rails. (In the Davis car resistance formula, the third term is both much lower and also less important than it is for the resistance of the locomotive. The importance of this 3rd term is offset by the MUCH greater total weight and surface area of the train, as any engineer who has ever hauled empty hoppers or double stacks knows.)

For the Commodore Vanderbilt, NYC believed there would be a coal and water saving on the mainline as the predominant wind direction was from the west, and they expected a coal and water savings between 2 and 12%.

To answer an earlier point, which was the first streamlined large steam engine?  It was the Commodore Vanderbilt, which was streamlined in the company shops from an earlier built conventional Hudson.  However, the first streamlined steam engine, actually built from the ground up was the Milwaukee Road's 4-4-2 Atlantic Hiawathas, built about a year later.

Interestingly enough is that in most cases the conventional engines that had been streamlined were ultimately shed of their shrouding and finished off their lives as conventional engines.  Actually the Commodore Vanderbilt only lasted about 3 years in it's original streamlined appearance, before it was re-shrouded in the Dreyfuss design like the newer engines of 1938.  In the case of the Hiawathas, both the Atlantics and the Hudsons, they never appeared in any other form than in their streamlined, shrouded form.  I think that this was true of most other RR's as well, that their streamlining remained, in some form, all of their service lives if they started out as streamliners.

Paul Fischer

https://en.wikipedia.org/wiki/LMS_Coronation_Class

The streamlining was removed from the fitted locomotives from 1946 onwards. It had been found to be of little value at speeds below 90 mph (140 km/h), and was unpopular with running shed employees as it caused difficulty of access for maintenance. Only three locomotives were still streamlined at the end of the LMS period and they had been stripped by the end of 1949.

I suppose there was a period when steam locomotives just didn't run fast enough to worry about streamlining. The early 1880s showed some European ideas, like filling in the wheel-spokes with wood and putting wedge shapes on anything facing forward, like cabs and smokeboxes. The French Coupe-Vents got lots of publicity, and has been stated above, the companies worked the PR angle for all it was worth. 

I'm not saying i am correct in my thinking.  It's an opinion of mine.  But I will say that since most trains travel at less than 90 or 100 MPH, streamlining does little for efficiency.  Again, just my judgment.  I think, as others have pointed out, streamlining did more for public relations than for saving fuel.  

Streamlining the loco provides some benefit at high speeds, but the rest of the train should also be streamlined for true high-speed service.

The "ears" are for air braking.

Looks "Foxy" to me.

Ralph M posted:

The attempts to streamline steam engines produced some truly gorgeous mechanical marvels. I was wondering though, were there any conclusive tests done to see if they went faster? Used less fuel/water? Or, any other real benefit other than the aesthetic? 

Thanks  

Some of the steam streamlining aesthetics were debatable.

Nashville Chattanooga & St Louis - City of Memphis locomotive - 1947

Hmm, looks like a brick wall coming at you. 

Guys,

The question of whether Streamlining a locomotive is effective or not is answered via the application of some physics F = MA.  

There have been some miss quotes given assigning weight and the aero components as being dependent upon one another.  

Below I've sighted a discussion that speaks to how tractive effort is calculated.  These equations are used every day by automotive engineers to determine the impact of weight, aero, rolling resistance and grade changes on Fuel Economy and Vehicle Performance.  It is important to understand that when speaking to the aerodynamics of a vehicle that we keep in mind the Cd and Frontal Area of the vehicle.  Cd known as the coefficient of drag is a dimensionless coefficient related to the object's geometry and taking into account both skin friction and form drag. 

As noted earlier, aerodynamic drag increases with the square of speed, thus it plays a critical roll at higher vehicle speeds.

The frontal area of a steam locomotive is very high.  Typically one would take the width and multiply height to get the area.  However as  you know it also has many, many nooks and crannies which increases the frontal area.  I can't even imagine what the FA of 765 would be for example.  It would be necessary to have it measured by a very specialized piece of equipment that uses laser technology.  This unit isn't portable and neither is 765 (very easily). 

Thus shrouding the engine (streamlining) would definitely significantly improve the engines aerodynamics by the elimination of openings and places where the air can become trapped.  And since it is speed dependent, it would benefit the operation by saving fuel costs.  The streamlining would also have to extend to the coaches as well, the gap between the cars would have to be closed, the sides smoothed and the entire undercarriage of the locomotive and cars would have to be streamlined as well.   This may be a surprise to some, but the streamlining of the undercarriage is very important.  In some cases a simple air dam and some streamlining extending just past the front wheels of a vehicle is enough to get laminar air flow under the vehicle. 

Additionally, the Cd of the whole train can be negatively impacted by cross winds which would increase the Cd value.

The mass of the locomotive comes into play only when determining the rolling resistance, inertia and grade forces. 

The following is from: ENERGY LOSSES FOR PROPELLING AND BRAKING CONDITIONS OF AN ELECTRIC VEHICLE   
by Lynn Rupert Gantt  (This paper can be found online).

A vehicle in motion experiences a set of forces (including road load), which determines the minimum FORCE at the wheels (known as tractive effort) required to meet a given speed and acceleration.

Tractive effort can be broken down into four main categories, tire rolling resistance (Frolling), aerodynamic drag (Faero), overcoming the current vehicle state of motion (Finertia), and finally the grade or inclination that the vehicle is travelling on (Fgrade). See Equation: 1

Equation 1:  Ftractive = Frolling +Faero +Finertia +Fgrade 

The individual components of the equations break down thusly:

Here, Crr0 is the coefficient of rolling resistance, Crr1 coefficient of rolling resistance affected by Velocity (not always included), m is vehicle mass, g is the acceleration due to gravity, P  (roh) is the density of air, Cd is the coefficient of drag, Af is the frontal area of the vehicle, V is the velocity for the drive cycle, Mi is an inertial mass factor term to account for the rotating inertia of the wheels, tires, and other rotating components, dv/dt is the acceleration from one time step to the next for the drive cycle, and Theta (related to grade) is the angle of incline.  For normal inclines, the cos(theta) term that could be included in Equation 2 is approximated as 1. 

Equ 2: Frolling = Crr0mg+ Crr1mgV

Equ 3: Faero = 1/2mgPCdAfV^2

Equ 4: Finertia = mMidv/dt 

Equ 5:   Fgrade = mgsin(theta)=mg∗grade 

Variable Definitions
Crr0   Static coefficient of rolling resistance [-]

Crr1 Moving coefficient of rolling resistance [-]

m Vehicle test mass kg

g Gravity m/s2

V Velocity m/s

P Density of air kg/m3

Cd Coefficient of Drag [-]

Af Frontal Area m2

Mi Inertia mass factor [-]

dv/dt Drive cycle acceleration m/s2

Theta Degree of inclination [theta] 

 Hope this helps answer some of your concerns.  

There was a posting earlier that quoted some similar equations, but that posting has since been deleted or edited.  Could the person who had the locomotive Force equations please post them again or provide a link to the article?

Thanks

I may be in the minority, but I find most streamlined steam engines to be very unattractive.

Opinion.

Bob, there are only a few streamlined designs that, in my option, are worthy of having a place on this earth.  Now I am speaking of steam locos only.  The NYC Dreyfus Hudson would be one along with N&W #611.  

Don't know if this adds or subtracts from the topic, but here's something to contemplate:   Milwaukee Road Hiawatha streamlined Hudsons  ran for some 400 miles (Chgo-Twin Cities) at very high speeds, for periods, above 100 mph. Un-streamlined Santa Fe 4-8-4's ran Ks City-LA at very high speeds, often above 100 mph, for long periods. Lack of streamlining seems to have posed no handicap on the ATSF locomotives' performance.

Santa Fe had one streamlined 4-6-4, the "Blue Goose", but did not replicate the streamlining on any other locomotive. My takeaway: no great operational benefit achieved.

To Allegheney's point, contemporary trucks have baffles underneath their trailers and wings on the back, so apparently the engineering on trucks indicates a bit of "streamlining" is beneficial. My bet, it is in the area of fuel savings, not top speed, but, then, would imagine those two factors being reciprocal.

mark s posted:

Don't know if this adds or subtracts from the topic, but here's something to contemplate:   Milwaukee Road Hiawatha streamlined Hudsons  ran for some 400 miles (Chgo-Twin Cities) at very high speeds, for periods, above 100 mph. Un-streamlined Santa Fe 4-8-4's ran Ks City-LA at very high speeds, often above 100 mph, for long periods. Lack of streamlining seems to have posed no handicap on the ATSF locomotives' performance.

Lets compare the two trains... MILW average trainset behind a Hudson was what, maybe 8-9 cars? Don't forget the MILW also had some nice 4-8-4's. Average ATSF trainset behind a Northern, probably 16+ cars???  Didn't the ATSF have to go through Raton Pass on this run too? MILW was pretty flatland running from MILW to ST.P.

And to add, I believe the MILW streamlined some Atlantics prior to the Hudsons, yes??

Steam fan:     yes, different train lengths, train weight and horsepower outputs, but top speeds comparable, whether behind a streamlined or unstreamlined steam locomotive.

mark s posted:

Don't know if this adds or subtracts from the topic, but here's something to contemplate:   Milwaukee Road Hiawatha streamlined Hudsons  ran for some 400 miles (Chgo-Twin Cities) at very high speeds, for periods, above 100 mph. Un-streamlined Santa Fe 4-8-4's ran Ks City-LA at very high speeds, often above 100 mph, for long periods. Lack of streamlining seems to have posed no handicap on the ATSF locomotives' performance.

Santa Fe had one streamlined 4-6-4, the "Blue Goose", but did not replicate the streamlining on any other locomotive. My takeaway: no great operational benefit achieved.

To Allegheney's point, contemporary trucks have baffles underneath their trailers and wings on the back, so apparently the engineering on trucks indicates a bit of "streamlining" is beneficial. My bet, it is in the area of fuel savings, not top speed, but, then, would imagine those two factors being reciprocal.

Regarding the Santa Fe's "Blue Goose" 4-6-4, at the same time the BLue Goose was being developed Santa Fe was also developing its 3765 class 4-8-4 (their first built new with 80" drivers and 300 psi boilers).  The plan was to build the first engine, 3765, with the same streamlining as the Blue Goose, but the Santa Fe felt that the extra weight of the streamlining was too much.

Stuart

An efficient steam locomotive has to be engineered from the ground up, I'd say, and not the hope and prayer of adding some streamlining to gain a little time. How about Mr. Porta's metre-gauge 4-8-0?

http://www.rypn.org/rypn_files...rgentina/default.htm

Firewood posted:

An efficient steam locomotive has to be engineered from the ground up, I'd say, and not the hope and prayer of adding some streamlining to gain a little time. How about Mr. Porta's metre-gauge 4-8-0?

http://www.rypn.org/rypn_files...rgentina/default.htm

locomotive was a metre gauge 4-8-0,   4 cylinder compound

That's an interesting item. It achieved higher efficiency but suffered the usual fate of experimental locomotives: greater mechanical complexity and higher maintenance costs. I doubt that the streamlining made it any faster.