Why do we call 'em diesels? They should be called "electrics".

T

thegrindre

narrow gauge fanatic
In actuality, the diesel engine is nothing more then a huge power plant generating electricity to the huge motors between each wheel set. The diesel engine itself has nothing to do with the pulling power of the unit, it's the electric motors between the wheels that do all the work. So, why do we call 'em diesels and not "electrics"?
 
thegrindre said:
In actuality, the diesel engine is nothing more then a huge power plant generating electricity to the huge motors between each wheel set. The diesel engine itself has nothing to do with the pulling power of the unit, it's the electric motors between the wheels that do all the work. So, why do we call 'em diesels and not "electrics"?
Click to expand...

I'd like to correct your viewpoint there...

The diesel engine does have a lot to do with the pulling power of the locomotive. The diesel engine does the work so the Traction motors can do their work. They cannot be called electrics because the way the transmission works is completely different to the way a standard externally powered electric train works.

That's why we call them Diesel Electrics.

And any mechanical engineer worth his salt knows that the available horsepower coming out of the engine at the flywheel dictates how much load he can put on the generator. In turn, this affects the pulling power at the wheels and thus the overall pulling power of the locomotive.

For example, a 1,000 horsepower locomotive would be able to lug a 750 ton train up a 1 in 75 (or 1.33%) grade at about 10 to 12 mph.

A 3,000 horsepower locomotive with the same weight, wheelsize, gear ratio and maximum speed would be able to lug the same train up the same hill at a much higher speed.

A 6,000 horsepower locomotive would scream over the hills with such a train.

regards

Harry
 
Why use Diesel-Electric transmission? In my opinion, Diesel Mechanical power would be much more efficient.
 
Kaleb said:
Why use Diesel-Electric transmission? In my opinion, Diesel Mechanical power would be much more efficient.
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Wrong again...

Diesel electric transmission is one of the most efficient methods of converting the chemical energy in diesel into pulling power at the rails with very little of the energy coming out of the generator intended for traction purposes being lost in the way of heat and friction. Of the 100% of power generated for traction purposes, 99% actually makes to the motors.

Diesel Hydraulic traction is less efficient. Because of the nature of these locomotives and the need to cool the transmission fluid, you'll loose a bit of energy in the movement of the fluid round the transmission system. Out of 100% of power produced for traction purposes, between 85 to 90% makes it to the wheels.

Diesel Mechanical traction is even less efficient. This is because the entire drive train and gearbox assembly friction has to be overcome before the shaft even starts to turn. then you also have to factor in that some diesel mechanicals will have a fluid flywheel into the bargain and you're looking at the fact that of 100% power generated by the engine, only 75 to 80% of it makes it to the engine.

Other advantages of diesel electrics are that all ancillary equipment can be driven by electricity whereas with diesel hydraulic and mechanical drives, that is mostly done by mechanical means. Another advantage over other types of traction is that both diesel-electrics and diesel hydraulics can still develop maximum power at low speeds - Something that a diesel mechanical design would be hard pushed to do.

And yes... Someone tried to design a Diesel mechanical locomotive and it was an utter reliability disaster...

regards

Harry
 
diesel mech. is mainly used in small shunting locos

hydraulic is the best in my opinon (HUGE fan of the Hymek!)
 
Well, back to the original question, the real reason they're called diesels is because the person who originally came up with them, was named Diesel.
 
kcdowdy said:
Is a train like a car?
Click to expand...

No.

kcdowdy said:
How much is the max a train can pull?
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Surely you are aware that there is more than one type of locomotive in the world?

Many factors affect the pulling power of a locomotive. Take two locomotives at random: An AC6000CW and an Re 460. Both have a similar amount of horsepower. Both use traction motors for propulsion. Yet the AC6000CW carries huge coal drags over the Rockies at low speed, while the Re 260 carries crampt and uncomfortable IC 2000 trainsets over the Alps at high speed. Switch the locomotives and the Re 460 can't even get going while the AC6000CW is being mobbed by angry Swiss commuters because it's only doing 90 km/h. (and covering the interior of Luzern Bahnhof with diesel smoke)

It's all in the gearing when it comes to this sort of thing. Even a 1hp motor could get a 6000 ton train going if it was geared properly. (Admittedly at a top speed of 0.00000678 mph, but that's beside the point.)
 
W you gotta think, a while back, Harry posted a mug of him, and it showed him, and his little Shunter he owns(am i right harry James?)
Cheers,
Sean
 
kcdowdy said:
How much is the max a train can pull?

Thanks.
Click to expand...
Ther is many things that can affect how much can be pulled. How many of what type loco are in the consist, the amount of tracktive effort they produce, weather the wheels and rail are new or out of spec on their profile (this effects the adheasion between the wheels and rails), how steep of grade they are pulling, how many and how sharp of curves they need to nagotiate, weather the locos have AC or DC traction motors or are mixed, the weather conditions the train will encounter (snow, rain, ice, heat, cold). The railroads have a formula for figuring out how much motive power they will requier to get the consist to its destination at the speed they want using the variables I mentioned.

Bill
 
the real reason they're called diesels is because the person who originally came up with them, was named Diesel.
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Did herr Diesel invent the Diesel engine? I thought it was more of a trade name, like calling all vaccuum cleaners Hoovers.

Chris.
 
Waite a second, did he invent the actual diesel engine or the diesel electric locomotive we're talking about here?
 
Last edited:
thegrindre said:
In actuality, the diesel engine is nothing more then a huge power plant generating electricity to the huge motors between each wheel set. The diesel engine itself has nothing to do with the pulling power of the unit, it's the electric motors between the wheels that do all the work. So, why do we call 'em diesels and not "electrics"?
Click to expand...
Because the power comes from the powerplant, what ever it is, so a steam plant that generates electricity is call a steam plant, ect. A solar plant, a atomic generator that produces electricity is titled by it power [SIZE=-1]CAUSE[/SIZE].
http://www.britannica.com/search?query=diesel-electric&submit=Find&source=MWTEXT
 
It's not like Honda or Toyota was the first to introduce the hybrid. Railroads have been using Diesel electrics since the 1930s.
 
SuperFudd said:
It's not like Honda or Toyota was the first to introduce the hybrid. Railroads have been using Diesel electrics since the 1930s.
Click to expand...

Not necessarily the way you're thinking. The Prius was the first serious attempt at a mass-produced motor car aimed at a price that the middle class could afford that can either use a diesel engine or batteries to move.

The UK rail industry built it's first serious attempt (ie. designed and built that way) with the class 73s. they were electro-diesels and they could either work off 750v DC third rail or a 600 horse diesel electric gen-set.

Class 31s were rumoured to be able to use their starting batteries to move them around yards in notch 1.

and MLVs had onboard batteries for traction purposes to move themselves around when the 'locomotives' were off the juice (and yes, MLVs are, despite their looks, Locomotives.)

regards

Harry
 
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