Unicorns, Bigfoot, Nessie And Now T H I S...

Last and largest of the steam locomotives, 6,290 HP:

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

The first diesels were low on power too. Just used for switching and had a manual transmission/clutch.

Boiling 85,000 lbs/hr water seems to convert to 4,630 hp. That would be thermal hp conversion not necessarily output power. Old steam was rated more in pulling power or tractive effort to start a load. HP of course needs a speed component and these monsters were never really put on a dynomometer. Peak hp would seem to be made at about 45 mph.

Large steam (4-6-6-2?) had huge air compressors to operate the brakes on the cars. Plenty of videos of old trains where smoke is coming from the brakes of every car as they descend.

A 6500 hosepower boiler would be about the size of an olympic auditorium. Working and going to college I fired a pair of B&W boilers. 160#. Consumed max 85000 lbs/hr water. Rated 160 hp.

I was referring to OLD steam engines not 2x6x2 monsters. With six drivers. Standard max boxcar load is 100 tons. A 135 carriage train of today requires a lot of power on steep grades. And they have to brake something a steam engine has trouble with.

Train locomotives are fascinating. We used to freak out commuters who were stopped in heavy traffic on a multiple rail crossing. Drive a pickup onto the rails at the next crossing. Stand on the bumper with a sealed beam spotlight. Then throw a pipe across the rails to activate the wig-wag. Switch on the light and revolve it slowly. The local cops caught on only too quickly.

I look forward to getting rid of the transmission of large vehicles. Just use an electric motor from 0 to about 50 mph and the engine could direct drive from 40 to 70 mph.

MEXICOWANDERER wrote:
Locomotive power is a term used "to set things to travel usually bearing a load".

New railroad locomotives are AC electric diesel. Older ones were direct current. Different meaning. MUCH of generated power is used for magnetism to bond the drive wheels to the track. Remember old-timey steam locomotives? Slipping drive wheels? Sand to increase friction? Think those guys were more powerful than your everyday ATSF transcontinental? Yes the implications are clear. Newer locomotives have one hell of an inverter aboard.

Quick search puts both at about 6500 horsepower.

Steam lost due to lower efficiency and higher maintenance cost. Not for power.

Pretty sure a modern diesel/electric could spin the wheels just as easy as steam. I assume better control of torque for the diesel/electric.

Magnetic bond? Have any link on that?... I have never heard of it.

jharrell wrote:

RSD559 wrote:
I understood that all modern locomotives are electric powered. The big diesels are to charge the batteries. The torque required to start a train rolling is immense. Electric motors are about the only thing that can produce that kind of torque.

There are no batteries, the electric drive train just replaces the transmission. You can get all the torque you want from gears, but a modern train needs very precise traction control to prevent wheel slippage. Much easier to do with electric motors than gears, however efficiency suffers. Mechanical transmission with gears is 95+% efficient, the double conversion from mechanical to electric back to mechanical in a train is under 80% but the trade-off is worth it to be able to get the thing moving properly. Also dynamic braking is useful too, just using motors to brake and electricity dumped to heat strips on roof.

OTR trucks and MH's are different, they dont need precise traction control they do need maximum efficiency at highway speeds though. Standard semi has 300 gallons of diesel and 2000 mile range. To do that with batteries your talking a 4-5 Megawatt-hour bank. That's a million dollar battery that weighs as much as your cargo.

So maybe do a 500 mile range with a 1 Megawatt-hour battery weighing 10k pounds for a days driving, then 10 hours to charge on a 100kw charger. What trucker would go for that? Will be interesting to see what Tesla shows in Sept.

Diesel-electric semi like a train? Why at highway speeds Diesel mechanical is more efficient, whats the point? Hybrid? Only helps in the city, nearly all hybrids connect engine to wheels directly on the highway for efficiency.

I like electric cars, perfect for commuting, decoupling fuel from vehicle is great. Today it runs off coal tomorrow solar, power plants are more efficient than small engines and can and do have more extensive emission controls. However its a long way off before we have batteries that make sense in long haul highway applications such as Semis and MH's.

There is more efficiency to be had in diesel mechanical, Cummins is showing a prototype with a secondary heat recovery turbine like a power plant, they tried driving electric with the turbine, found it was more efficient just to mechanically feed it into drivetrain.

Good and interesting post. I agree with moving the pollution problem to the grid and away from personal vehicles and city busses. As the grids get cleaner the pollution is less and the air gets cleaner. Many countries already get most or all their power from renewable or low polluting sources. Others not so much but I don't think anyone doubts that the trend on a world wide basis will be towards a cleaner grid. Some countries will lag behind but as the technologies get cheaper it won't make any sense to produce power from coal and at some point even natural gas. It will be like it always is, a question of economics.

RSD559 wrote:
I understood that all modern locomotives are electric powered. The big diesels are to charge the batteries. The torque required to start a train rolling is immense. Electric motors are about the only thing that can produce that kind of torque.

There are no batteries, the electric drive train just replaces the transmission. You can get all the torque you want from gears, but a modern train needs very precise traction control to prevent wheel slippage. Much easier to do with electric motors than gears, however efficiency suffers. Mechanical transmission with gears is 95+% efficient, the double conversion from mechanical to electric back to mechanical in a train is under 80% but the trade-off is worth it to be able to get the thing moving properly. Also dynamic braking is useful too, just using motors to brake and electricity dumped to heat strips on roof.

OTR trucks and MH's are different, they dont need precise traction control they do need maximum efficiency at highway speeds though. Standard semi has 300 gallons of diesel and 2000 mile range. To do that with batteries your talking a 4-5 Megawatt-hour bank. That's a million dollar battery that weighs as much as your cargo.

So maybe do a 500 mile range with a 1 Megawatt-hour battery weighing 10k pounds for a days driving, then 10 hours to charge on a 100kw charger. What trucker would go for that? Will be interesting to see what Tesla shows in Sept.

Diesel-electric semi like a train? Why at highway speeds Diesel mechanical is more efficient, whats the point? Hybrid? Only helps in the city, nearly all hybrids connect engine to wheels directly on the highway for efficiency.

I like electric cars, perfect for commuting, decoupling fuel from vehicle is great. Today it runs off coal tomorrow solar, power plants are more efficient than small engines and can and do have more extensive emission controls. However its a long way off before we have batteries that make sense in long haul highway applications such as Semis and MH's.

There is more efficiency to be had in diesel mechanical, Cummins is showing a prototype with a secondary heat recovery turbine like a power plant, they tried driving electric with the turbine, found it was more efficient just to mechanically feed it into drivetrain.

Locomotive power is a term used "to set things to travel usually bearing a load".

New railroad locomotives are AC electric diesel. Older ones were direct current. Different meaning. MUCH of generated power is used for magnetism to bond the drive wheels to the track. Remember old-timey steam locomotives? Slipping drive wheels? Sand to increase friction? Think those guys were more powerful than your everyday ATSF transcontinental? Yes the implications are clear. Newer locomotives have one hell of an inverter aboard.

I understood that all modern locomotives are electric powered. The big diesels are to charge the batteries. The torque required to start a train rolling is immense. Electric motors are about the only thing that can produce that kind of torque.

H6N7 ??