train efficiency

[mjolnir]

"Reciprocating" means back and forth, and refers to the movement of the pistons in the steam cylinders. The energy to move the train was transfered from the pistons to the drive wheels by means of drive rods which moved the wheels in a circle. Now, try this: mark a point on a driver at the edge of the wheel, on the line of the radius of the wheel, and watch the path that point makes as you rotate the circle. Every time the point on the edge of the wheel reaches the bottom of its path, it is like a large hammer beating on the track structure.

ns

 

[Harry_James_Potter]

Two major accidents in 65 years? I don't call that dangerous. Plus, modern reactors are physically incapable of melting down through simple mishandling of equipment (as in Chernobyl) and can use fuel until it is entirely spent and a=safe to be out in the open.

That has to be the weirdest view of nuclear power I've seen.

If only you knew the truth...........

regards

Harry

 

[Gandalf0444]

Can anyone say nuclear power? And we ain't talking about pollution here, we're talking about efficiency.


I'd personally say the electric locomotive is the most efficient locomotive imaginable. Why? Regenerative braking, that's why. Regenerative braking turns the traction motors into generators, slowing the train and feeding the kinetic energy back into the power lines. This is an extremely effective system. For example, the Milwaukee Road electrified its line over the Rockies. The first train sent over used regenerative braking. When the Milwaukee road received the electric bill for that particular trip, it was found that the electric company owed it $1.64.

Saying that Nuclear power doesn't pollute! When the uranium is spent where do you think it goes? Do you think they flush it down the toilet to the water treatment plant? No they stick it in a mountain some where in some metal drum and wait for it to(lack of a better term) lose its strength and wait until its no longer radioactive and then it can get put in the ground or whatever the companies do with it. If you think Nuclear power plants don't create pollution your sadly mistaken,sure they don't blow toxic smoke into the air but you always have that uranium toxic waste moving around and in a mountain sitting there for coutless years. But thats not pollution? And what about all the resources needed to keep the transport safe and all the stuff that they use at the moutain storage area to keep it safe,im sure you don't think about how much more stuff you need to make all that stuff?

 

[Harry_James_Potter]

If you think Nuclear power plants don't create pollution your sadly mistaken,sure they don't blow toxic smoke into the air....

Another mistaken view on nuclear power...

AGRs and Magnoxes both discharge their Carbon Dioxide coolant from time to time because it breaks down under the intense neutron bombardment and obviously, you don't want gaseous oxygen in the same place as a 500C lump of graphite.

The same goes for the PWR, BWR and Candu reactors who all have to discharge a little of their coolant now and then due to breakdown.

And the RBMK designs are the real kings for generating gases that need to be removed and disposed of... The graphite core of an RBMK is surrounded by a mixture of gases (yes, the reactor type is water-cooled in the main) that are mainly there to insulate the core from any air that may enter the pressure vessel. While these reactors are running, they generate a fair bit of hydrogen gas from the breakdown of these gases and the odd bit of coolant. This has to be vented to air and the original preferrence was to burn it off.

Either way, it's still only about 30% efficient.

regards

Harry

 

[RooRocz]

Saying that Nuclear power doesn't pollute! When the uranium is spent where do you think it goes? Do you think they flush it down the toilet to the water treatment plant? No they stick it in a mountain some where in some metal drum and wait for it to(lack of a better term) lose its strength and wait until its no longer radioactive and then it can get put in the ground or whatever the companies do with it. If you think Nuclear power plants don't create pollution your sadly mistaken,sure they don't blow toxic smoke into the air but you always have that uranium toxic waste moving around and in a mountain sitting there for coutless years. But thats not pollution? And what about all the resources needed to keep the transport safe and all the stuff that they use at the moutain storage area to keep it safe,im sure you don't think about how much more stuff you need to make all that stuff?

New (post-2007) reactors have the capability to utilize uranium until it is completely depleted, at which point it can be disposed of as normal hazardous waste, or made into ammunition.

 

[johnchisem]

New (post-2007) reactors have the capability to utilize uranium until it is completely depleted, at which point it can be disposed of as normal hazardous waste, or made into ammunition.

Ho, so that makes it hunky-dory then?

John

 

[Gandalf0444]

I guess it does.

 

[johnwhelan]

Saying that Nuclear power doesn't pollute! When the uranium is spent where do you think it goes? Do you think they flush it down the toilet to the water treatment plant? No they stick it in a mountain some where in some metal drum and wait for it to(lack of a better term) lose its strength and wait until its no longer radioactive and then it can get put in the ground or whatever the companies do with it. If you think Nuclear power plants don't create pollution your sadly mistaken,sure they don't blow toxic smoke into the air but you always have that uranium toxic waste moving around and in a mountain sitting there for coutless years. But thats not pollution? And what about all the resources needed to keep the transport safe and all the stuff that they use at the moutain storage area to keep it safe,im sure you don't think about how much more stuff you need to make all that stuff?

But on the other hand they dug radioactive material out of a mountain to start with so putting some back doesn't sound too bad unless I'm missing something. These days the trendy thing is not to depend on jmetal drums any more but put it in a lump of glass.

Any way you could always store the waste in Glasgow, the background radiation there is fairly high so a bit more wouldn't be that noticeable.

Cheerio John

 

[smash]

On the note of Nuclear power plants. An active plant stores its used nuclear fuel in a water holding tank on site. What happens to it when the shut down a plant I dont know.
Back on subject.

I would venture to say that each form of locomotive has its niche.
Steam is the most inefficient but the one alot of people will pay to see and ride on.
Diesel is much better suited to freight and long distance passenger. (I speak mainly for the US.)
I would say that most railroads would love to go electric. Execpt that the cost to convert would be astronomical. The other half of that is the burden put on (again mainly the US) electric system.

So for the most part electric seems to work best for passenger.

Do not get me wrong I do realize that there are places and country's that successfully use electric power for freight.
Just my



Kenny

 

[randknu]

Just dug up this old thread. I have some neat input to share.

Here in norway we are pretty much self supplied with hydro-electric power. And almost all the trains in norway are electric. The modern electrics using AC-traction motors have regenerative braking.

Theese beasts have over 14000 hp per pair and when used to haul iron ore from Kiruna, Sweden to Narvik, Norway which is mostly downhill they will generate more power than they use. This power is then used to pull the empty trains back up to Kiruna! How is that for efficancy?

Yes electrics use electric power and is best suited for areas where there is ample supply of electric power. The milwaukee road used electrics over the rockies because:
1. At the time the only alternative was steam.
2. Long tunnels made it problematic for engineers to survive the smoke and dust a steam engine would make inside the tunnels.
3. The rocky mountains meant hydro-electric power was cheap.

It's strange but the milwaukee might have survived if they had upgraded the electrics instead of converting to diesel during the fuel crysis in the 70s.

The biggest problem for milwaukee's electrics was that they used 3000V DC, and direct current cannot be transformed so they had to use 3000V onto the traction motors and regulating it with resistors. I do not believe they ever had regenerative braking back then. This system was far from efficient, lots of heat loss in the resistors and in the overhead wire meant that efficiancy must have been around 50% or less.

Here in norway we use 16000V 16 2/3Hz AC in the overhead wire. The low frequency was neccesary for the early serial wound comutator traction motors. 16000V means that 5 times as much energy can be transferred through the same wire. compared to 3000V. This means there is a lot less heat loss and thus has higher efficiancy. Most of the locomotives we have here in norway have about 90% efficiancy.
This means that 90% of the energy going into the pantograph is being used to power the locomotive. And since it is alternating current we have transformers in the locos to transform the energy into the voltage that is best suited for the traction motors.

So... The most efficient locomotive? it's the electric with AC traction motors hands down no matter where the energy comes from.

But it is most efficient in areas where environmentally friendly energy can be made (such as from hydro-electric powerplants in mountaineus areas)

 

[Tokkyu40]

Electric is the most efficient. The generator can always be run at it's most efficient speed, unlike a diesel locomotive where the peak efficiency is only occasionally reached. Even with coal fired power plants, electric cars result in a carbon emission equivalent to about 40 mpg, and hydro, geothermal and other renewables extend that considerably. Trains would get similar benefits.
Modern steam locomotives can take great advantages of their advances to reach very high thermal efficiencies with the steam, but the transition from water to steam (the heat of vaporization) takes a huge amount of heat and destroys any efficiencies you can get elsewhere in the cycle.
Nuclear waste can be collected in large water tanks and used to drive sterling engines to generate even more power.

Claude

 

[gisa]

I second that. A modern electric with regenerative braking has to be the most efficient over a given period of time. However, when factoring in the costs of electrification, it only makes sense for high density traffic and when a need to upgrade locomotives exists. The energy required to bulid anything also has to be taken into account too.

I'd rate the newer diesels second in that sense because as Claude and everyone else has said, it takes a lot of coal/oil/wood to make the water hot enough to make steam. As well as factoring in the maintenance costs of running steam locos, it's little wonder why most railroads around the world started dieselizing their fleets in the 50's/60's.

For what it is worth, every source of electricity has problems. Solar and wind power are unfortunately unreliable and are smaller scale, coal, oil and natural gas are dirty (from most to least), nuclear power requires a lot of capital to get going, gives off waste in some form and there is a threat of a meltdown if the plant is designed/run poorly (i.e. Chernobyl). Hydroelectric can also require a lot of capital to get going, wreck havoc on local ecosystems/industries (i.e. fishing), displace people (Ganges Dam is it? in China) and since the density of people who live near mountains generally isn't high, transmitting the electricity over long distances becomes less efficient and more fragile (better chance of something disturbing the line). Don't even get me started on biodiesel...:hehe:

The way things are now, I'd go with a mix of solar, wind and hydro and nuclear to help offset anything with regards to coal, oil and natural gas. Cheap energy is likely a thing of the past the way things are going. Factor in the increasing population, the increasing rate of consumption and well...sucks to be us. However, many smaller cities and communities can benefit greatly from these types of power plants. I just hope it starts to happen now than later...

:wave:

Gisa ^^

 

[themnax]

The following is a quote from http://exotic.railfan.net/dieselfaq.htm

"11. Exactly why did the diesel-electric locomotive replace the steam locomotive?
A. Thermal efficiency of a diesel is about 30%, compared to 6-7% for a steam locomotive. The diesel is therefore much more fuel efficient.
B. Diesels develop maximum horsepower and efficiency over a wide range of speeds. Steamers have a very narrow speed range in which they reach full efficiency.
C. Diesels can be operated in multiple units(MU) under only one set of controls. This means that 1 unit can control many other units. This allows once crew per train and greatly reduces labor costs.
D. Dynamic Braking allows good speed control on downgrades and reduces brake repairs. Longer trains are also allowed with better speed control.
E. Maintenance costs are very low in comparison to steamer. Diesel locomotives have an availability of 90% or better, compared to 30-40% for the average steamer. Standardized and modular design played a major role in the diesel's advantage over steam. A diesel could replace about 10 steam locomotives.
F. Fewer fuel and water stops.A diesel requires little water. Diesels allowed the retirement of $50,000,000 worth of equipment to supply water to very thirsty steamers.
G. A low center of gravity enables higher train speeds on curves.
H. Unlike steam locomotives, diesels do not stress the track with the pounding force of reciprocating components. Track maintenance is reduced as a result."

Bob

i think you missed one of the big ones, although it's implied in e: maintainence costs, though not spelled out there, and that is duty cycle/availability. maintainance of steamers is absolutely vital to their not becoming deadly dangerous, with a typical availability cycle of less then 50%, while a diesel electric, can be allowed to go to hell until it just falls apart and stops running. generaly of course its also uneconomical to neglect their maintainence entirely, but unlike a steamer spending 50% or more of its time in the round house, diesels (and electrics) spend less then 10% of their time in the shop. (diesel hydraulics can become dangerous from neglectied maintainence by that i forget what its called, hydraulic coupling, its bearings freezing up in service and tearing up the inside of the cab, the one that's mounted under it. that's what happend to sp's experiment with hydraulics, why the unions refuse to operate them, but even then, we're talking less maintaince time, where the're more common in europe, and presumably more rigorously maintained to keep them safe)

=^^=
.../\...

 

[BStyles]

I third to regenerative braking and electric trains. Trains that give power back to overhead wires or third rails are saving power plants the time to produce as much energy and the costs. Here in New York, subway cars and railcars such as the R142, R143, R160, M7, the new M8 and R179 all use regenerative braking.

It's also the first step to becoming an eco-friendly world.

 

[TSwenson]

What is Efficiency?

The first thing we need to do is to define efficiency in a railroad locomotive. The rail business community has done this since it's inception as cost per mile. Thats a hundred and what years of precedent? I think that the best way to define efficiency would to say "total cost" per mile/ton (km/tonne). Total cost is taking into account all costs involved everything from fuel and maintenance to environmental damage.

What did it cost, in adjusted pricing, to even lay the rails that the trains run on? What is, or was, the cost to add those wires over said track? Do we even know the staggering environmental damage done by the construction of the railroad? The answers to these questions will probably astound you, as will your reaction to them.

The most efficient loco? Alternating current electric with regenerative braking on an existing system using electricity from hydro or some other "green" renewable source is my best guess.

One thing that does stand out is that reciprocating steam locomotives are generally considered the least efficient locomotive. However one must realize that the technology of the steam locomotive stopped being improved upon, as a railroad locomotive, in any significant way almost fifty years ago.