Locomotive power

[Anonymous]

Engineering question.What's the maximum amount (tonnage) of fully loaded freight cars that an 5,500 horsepower locomotive can pull without a helper locomotive?.
Also, is there an advantage of a having a turbo-charged engine as opposed to a naturally aspirated one of the same horsepower?

[espeefoamer]

Turbo chargers pull more horsepower out of each cylinder.For two units to have equal horsepower,the normally asperated unit would need more cylinders.Turbocharging is more economical and fuel effecient than to provide extra cylinders for a normally asperated engine of the same HP.

[corwinda]

The tonnage question has too many variables to give a simple answer. For instance wind resistance varies with the car type. (For loads; TOFC most and solid strings of hoppers, gondolas, or tank cars the least. Mix car types and the wind resistance increases because there are more car ends pushing through the air.) Weather can also be a factor. (Rain or snow reduces traction, wind direction & velocity.)

Then add in grade and curvature.

[csxengineer98]

it all depends on ....
the rules of the railroad.... the amount of trailing tonage is alowed behind an empty long car.... the % of the grade in grade tarritory....
all come into play....and we dont go by HP of the locomotive..we go by the tonnage rating of the unit......each class of unit has a tonage rating for evey terriotry.... and on segmants of a territory...and we use the tonnage rating to add up how much power we have and how much the train weighs.....we subtract the diffrance..and if the tonnage is more then the tonnage rating of the power...we are going to need a helper on that territory....
csx engineer

[dehusman]

Just "pull"?

Probably somewhere in the neighborhood of 15-20,000 tons.

The CNW used 1 C40 to pull 100 car (13,000 ton) coal trains in the PRB.

Now if you are talking about a speed over 30 mph or any hills, it changes everything.

Dave H.

[Overmod]

... and don't forget top speed, expected acceleration, and number of anticipated slow orders or speed restrictions (with expected recovery times).

Diesel engines generally love turbochargers -- to understand why, think for a moment about how diesel engines work. Theoretically a diesel can reach 100% combustion of its injected fuel, because there can be an excess of air (and hence of oxygen) in the cylinder over what is required to burn all the fuel, and all that air has been heated above the transition temperature for ignition by compression (and, of course, the more fuel that burns, the more heat is present thereafter). From this, it follows that you can't inject more fuel than can react with the available oxygen in the cylinder -- you'll get black smoke and weird pollutants if you try. (Ask Adrianspeeder about smokin')!

Turbocharging uses some of the residual heat in the engine exhaust (which would otherwise be wasted in heating up the atmosphere) to compress the intake air before it goes into the engine. Result: more oxygen per stroke to react, therefore more fuel can be burned per stroke, therefore more power out of an engine the same size.

The issues with turbocharging on locomotives have to do with cost and maintenance problems. The turbos that are used are of considerable size, and don't have a particularly long service life (3-5 years is what I've heard 'round the industry). Worse, when one fails, it can cause a range of problems up to and including shrapnel damage and incinerated locomotives -- and I don't include problems related to the fact that a turbo'ed engine won't run well, if at all, with the turbo out.

Do not expect to find locomotives much above 2000hp without turbocharging. Somebody tell me how this "5,500 hp locomotive" was determined -- no one to my knowledge has ever built a single locomotive (or even a factory consist) with that rating. I don't think anyone has called a multiple-unit consist a "locomotive" since the '50s, although there were some early attempts to do so (e.g., a "5400 horsepower" locomotive composed of two FT drawbar-connected A-B sets was used on some railroads, ATSF for one). Are you perhaps looking at steam-locomotive 'horsepower' curves and extrapolating to a diesel equivalent?

[Anonymous]

I thank all you guys who responded to my questions, as my background has been with tugboats there are many similarities between the two. Your knowledge is astounding. It seems based on the last response i got there are'nt many locomotives with 5,500hp powerplants as opposed to tugs, it is very common to have high horspower powerplants when you're towing ships sometimes a 1,000 ft or more in length.Turbo's in tugs last a lot longer than locomotives from what i gather. Thanks fellas!!!

[M636C]

Overmod,

Although probably best forgotten, the three UP Alco Century 855s were each 5500 horsepower, from two 16-251E engines each. Now what could possibly go wrong!

With EMD engines, turbocharging brings fuel economy benefits, since at notch 7 and above, the exhaust pressure uncouples the turbocharger from the crankshaft, and makes more cylinder power available in the generator.

But 4300HP to 4400HP is the preferred power rating right now, after 6000 HP engines were found to have higher maintenance costs.

Peter

[Anonymous]

Not for CSX. They are rerating all their AC6000's back to 6000hp and they plan to order more 6000 hp units in the future. A CSX employee on another forum said they are definetly working with GE to produce a 6000 hp Evolution Series locomotive.

keep asking keep learning

[adrianspeeder]

Diesel???? Turbo???? SMOKE???

Sweeeeeeet.

A diesel engine is completly dependent on how much air it can draw in on the intake stroke. A turbo is simply there to force more air into the bore. More air = greater heat when compressed and more oxygen to burn when the diesel is injected in.

There has been some great discussions on diesel power in the forums before. Read this.

http://www.trains.com/community/forum/topic.asp?page=1&TOPIC_ID=17872

http://www.trains.com/community/forum/topic.asp?page=1&TOPIC_ID=18213

Welcome to the forums too. ANYthing you have a question about, post it. There are so many people that are specialized in somethings you would never think of. Also lots of fun goin on here too. Fill in your profile as much as you are comfortable with and start havin fun!!! (check out my pix too)

Adrianspeeder

[Anonymous]

Mr. Majorhat1 go to the GE locomotive site and they have tonnage charts for all their locomotives. The AC6000 is rated at 61,000 tons for level track and no curves.

keep asking keep learning

[dehusman]

Marine applications have always been easier on engines. Virtually all locomotive diesels owe some part of their ancestry to marine engines. Some were strong enough to make the transition, some weren't.

Dave H.

[CSXrules4eva]

One of the advantages of having a turbocharged engine is improved fuel economy and emissions. Two things diesels have trouble w/. This is so because of diesels' high compression ratio. Turbos increase power output by forcing air into the engine under pressure by either an exhaust fan or a blower. Trubos are ideal for many diesel and gasoline engines that are subjected to a very stressful engine load, such as a SD90MACH II (V16265H enine) pulling a fast intermodel on a 2.5% grade. This is so because the hot exhaust gases flow rapidly (when an engine is under high load) which in turn spins the turbine wheel, which is connected to the turbo shaft which spins the comopressor wheel. Compressor wheel rotation pulls air into the compressor housing. Cenetrifugal force throws the spinning air outward. This causes air to flow out of the turbo and into the engine cylinder under pressure. This is the basics of how a turbo works.

[Anonymous]

Engines destined for a marine application almost always highest rated for a given engine than if they were being configured for another mobile application because of the cooling capacity of the heat exchanger system used.

Marine engines can commonly have exhaust manifold and turbo charger coolant jackets in addition to lube oil and engine coolant heat exchangers that pass heat to "raw water" sea water.

Many engines have cover plates over accessory drives in land based applications that are used in marine applications for auxiliary pumps for marine applications.

It is also common to find pipe plugs in blocks and heads for the same reasons.

Marine engines by the nature of their use have to develop high horsepower at a steady rate for long periods of time.

Because of the higher heat generated from higher horsepower, it can be said that marine engines live and die by their cooling system.

High humidity and salt water are hardly friendly environments.

[Anonymous]

http://www.n0kfb.org/rail/railphs.htm

[Anonymous]

The first few DDA40-X "Centennial"s were originallydelivered at 7000 hp but were detuned to 6600 hp by an injector change. The remainder of them were manufactured to deliver 6600 hp. Of course that was from two prime movers. EMD 16-cylinder 645E3A.

[Anonymous]

N&W used to haul 240-car coal trains, about 21-22,000 tons, from Williamson, W. Va. to Portsmouth, O., with two GP30s or GP35s or one of each. There was an 0.3% grade against them over the Ohio River Bridge at Kenova, which they'd usually make unless it was too rainy.

But they'd go the entire distance without making their 27 MPH transition . . .

Old Timer