UP (the big locomotive railroad) ran their monsterlocos until mounting operating expenses relegated them to the dead lines - while smaller, simpler 'standard' designs kept on rolling.
When each unit of motive power had to have its very own crew it made sense to make each one as big and powerful as possible. Now a single engineer can control as many units as the railroad wants to connect together. That kills the need to max out each individual unit.
One other item. If something major requires shop attention, that bigger, more powerful locomotive takes a bigger bite out of available train-moving capacity, and will probably take longer and cost more to fix.
History is replete with examples where 'biggest' was not most efficient. That's why humongu-anythings tend to be one-off experiments. When there is a legitimate need for a bigger, faster or more powerful (fillintheblank) the need will be identified and driven by market forces - but not until the need is demonstrated - again, by market forces.
Chuck
Every step forward in the HP war is done at the behest of improved efficiency. Three Dash 8-40Cs were more efficient than four SD40-2s and Two AC4400s are more efficient than three Dash 8s and so on. There will be a next step eventually but right now the railroads (and our suppliers) have bigger problems to deal with.
Editor Emeritus, This Week at Amtrak
This is not going to be a defining answer about....
Couplers, and knuckles, (specifically the designed weakest link of freight cars) which had designed stress levels.
The common knuckle could pull against 240,000 lbs of train resistance, (resistance...If your baby weighs 8 pounds, until you lift with more than 8 pounds energy, the babe won't lift from the cradle, or the crib...
Those numbers are from the early 80's. So am I.
The E knuckle could pull against...330,000 pounds?
Metallurgy matters?
Sure does.
7000hp? No, 5000hp is really the limit of what's useful/efficient and 4000-4400hp is a good level for the RRs. AC traction has been the bigger factor more than anything.
ML
oltmannd A 6000 HP six axle is about it, for now. You gotta have a "grade E" knuckle train in order put 3 AC locomotives on the head end. 2. Smaller units and more evenly distributed DPU. 3. Reduced in-train forces. Reduced draft system failures. Easier block swaping. DPUs radio relay for more robust DPU signals front to rear.
A 6000 HP six axle is about it, for now. You gotta have a "grade E" knuckle train in order put 3 AC locomotives on the head end.
2. Smaller units and more evenly distributed DPU.
3. Reduced in-train forces. Reduced draft system failures. Easier block swaping. DPUs radio relay for more robust DPU signals front to rear.
Tier 4 ??. Anyone else note what NS is doing?? As well as others?. Tier 4 sucks, plain and simple. For those who love the EPA and regulations made by "carbon counters" Its easy to prove how stupid it really is. Most think that The carbon output causes a "greenhouse gas" and that raises temps, its a pretty much given in the way its explained today to the masses, BUT Tier 4 has HUGE maintenance costs involving the stacks, and filters, and the stack temps are 20 times what they are with tier 2 regs. To see for yourself go find a brandy new 18 wheeler with tier 4 and point your laser IR thermometer at the stack. The EPA didnt want this on trains so they told them they had to cool it some, and how much does this mess weigh and cost to maintain?? For over the road truckers Tier 4 trucks will STOP running if the filter isnt serviced by a SERVICE center....
Tier 3 already has Diesels running at faster RPM to make the emissions ( which uses more fuel, so more injection engineering, etc, big rat race. For the amount of work a SD70 does, its pretty darn efficient...and its NOT new..
You see how many tenders they need fro a CNG train engine>? the cost to make CNG is still more than its worth to sell.. It has to be purified and condensed, now you have a big rolling bomb... IF you have been in the Navy or around ports you'll notice they CLEAR the harbor for LNG or CNG tankers.......hows the first derail gonna look like??
Getting efficient is great, making MORE heat and more cost and more problems at the expense of others makes NO sense. Railroads cannot compete with tier 4 engines on their trains...
oltmannd I think the opportunities for future motive power might be: 1. Braking energy recovery. Lots of BTUs can be reclaimed and reused. Gets rid of a lot of the fuel penalty for braking vs. coasting. Could help raise avg train speed a bit.
I think the opportunities for future motive power might be:
1. Braking energy recovery.
Lots of BTUs can be reclaimed and reused. Gets rid of a lot of the fuel penalty for braking vs. coasting. Could help raise avg train speed a bit.
GE was promoting a hybrid locomotive 5 to 6 years ago, remembered the battery was good for about 2000HP equivalent, can't remember if it would last a half hour or an hour. A battery with high power density or ultracaps might be great for a commuter locomotive.
One application for a hybrid freight locomotive would be on a line with a long tunnel - running the diesel prime mover at half power with the battery picking up the other half would reduce the amount of crap that has to be blown out of the tunnel before another train can use it.
2. Smaller units and more evenly distributed DPU. Reduced in-train forces. Reduced draft system failures. Easier block swaping. DPUs radio relay for more robust DPU signals front to rear. Smaller units might not all have cabs - would use RCO-like devises for switching/building trains.
Reduced in-train forces. Reduced draft system failures. Easier block swaping. DPUs radio relay for more robust DPU signals front to rear.
Smaller units might not all have cabs - would use RCO-like devises for switching/building trains.
A 6000 HP six axle is about it, for now. You gotta have a "grade E" knuckle train in order put 3 AC locomotives on the head end. So, there would be limite opportunities to go 2:3 with a B-B+B-B locomotive.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
WM7471 Is it time for the locomotive manufacturers to come up with a new more powerful locomotive? Despite the oddballs that exist at large railroads (AC-6000s to gensets) the railroads have pretty much come to rely on 3 groups of locomotives: 1. 4000 to 4400 Hp 6 axle (even though some only have 4 traction motors), 2. 3000 Hp 6 axle 3. 2000 to 3000 Hp 4 axle. My thought would be for a locomotive that would be able to replace AC 4400s on a 2 for 3 basis, just like the 4400s did to the 3000 Hp SD40-2s. Tier 4 compliant 7000+ Hp with a single power plant. Most likely a B+B-B+B with movable bolsters for flexibility (unlike the old EMD DDs) Possible use of LNG or CNG Possible use of either LNG, CNG or diesel fuel tenders. If GE could come up with at 20 cylinder GEVO it would be in the 7000 Hp range, and who knows what EMD has in the Cat motor grab bag.. Just my thoughts, what are yours?
Is it time for the locomotive manufacturers to come up with a new more powerful locomotive?
Despite the oddballs that exist at large railroads (AC-6000s to gensets) the railroads have pretty much come to rely on 3 groups of locomotives:
1. 4000 to 4400 Hp 6 axle (even though some only have 4 traction motors),
2. 3000 Hp 6 axle
3. 2000 to 3000 Hp 4 axle.
My thought would be for a locomotive that would be able to replace AC 4400s on a 2 for 3 basis, just like the 4400s did to the 3000 Hp SD40-2s.
Tier 4 compliant
7000+ Hp with a single power plant.
Most likely a B+B-B+B with movable bolsters for flexibility (unlike the old EMD DDs)
Possible use of LNG or CNG
Possible use of either LNG, CNG or diesel fuel tenders.
If GE could come up with at 20 cylinder GEVO it would be in the 7000 Hp range, and who knows what EMD has in the Cat motor grab bag..
Just my thoughts, what are yours?
Cat does have the C280 engine series, the 16 cylinder version can produce over 7,000 BHP. GE had an 18 cylinder HDL engine test unit (never installed in a locomotive) which was rated at around 7,000 BHP so hypothetically a GEVO version could be developed.
two major problems:
1. the split cooling systems required for Tier IV compliance are very heavy and take up a lot of space, so much so that I have read that even the currently marketed 5,000-6,000 HP units (i.e SD80Ace (some sold to a Brazilian RR),ES58AC (ditto) and the Chinese AC60/SD90MAC derived units) would not meet weight requirements if fitted with the upgraded cooling systems.
2.Which leads us to the truck considerations-there are double BB connected truck systems currently marketed by both EMD and GE, primarily for narrow gauge applications (in Brazil again). I just read that GE is offering a narrow gauge ES44AC With bolster connected BBBB trucks (Yep, to Brazil). So it is technically possible. But the Class 1 railroads in North America are big on standardization and seem very satisfied with current truck designs so it would be a hard sell. You could use a 6 axled truck with larger wheel diameter. there is such a truck on the market, the one manufactured by Bombardier for the Swedish Class 26 IORE locomotive, which has a HP rating of 7,200 HP. The truck has AC traction motors and the wheels are over 49 inches in diameter (ES44AC wheels are 42 inches in diameter.).
A locomotive maker (and keep in mind that both manufacturers R&D efforts are largely tied up in getting their existing offerings to meet Tier IV, hasn't been an easy program esp. for EMD. A heap of money would have to be spent in developing a radically new locomotive line, and I would bet that none of the "Big 7" would place an order before the bugs were worked out.
However as engine technology advances I would not be surprised to see 5,000 HP or higher road locomotives being offered again to the North American Market.
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Also consider that for long, heavy trains, DPU in mid or end train positions helps alleviate the need for big honking power up front, so you can use 4 4K ocomotives, 2 up front, 2 in the middle, such that a 7K locomotives would be overkill.I suppose modular genset style engines would reduce excessive fuel consumption of a proposed 7K to some extent, but still you need to lug around the unused units, which still require some maintainance also.
The limiting factor in locomotives is wheel slip control - all the horsepower in the world does no good if you are just spinning your wheels. The 4000-4400hp AC 6-axles have maxed out current wheel slip technology. For anymore HP, wheel slip technology will have to take another leap forward.
Never too old to have a happy childhood!
I don't think that it's going to happen. The three groups listed cover almost every conceivable service requirement and the various manufacturers have them covered quite nicely. There doesn't seem to be any need for a super-size locomotive at this time. About 50 years ago, the Big 3 builders catalogued and built super-size locomotives (C855, U50, DD35) but there was no real demand for them beyond Union Pacific.
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