Just as the title says. I've seen a few people here who work for railroads complain about the new genset engines saying that they are always breaking down. What is it about them that is so unreliable? Do individual generators go down? Traction motor problems? Electrical issues? Just looking for more insight as to why they seem so bad in this regards. I see them everywhere here around Houston. The concept seems sound so I'm wondering what isn't working out quite right?
They are still relatively new technology, maybe things aren't perfected yet. I know that these are supposed to be one of the big things of the future of railroading. And hybrids, I guess.
The short answer is they have more components - thus more items to maintain and more items to break. Long answer is more about the differences in duty/load cycles between locomotives and the applications that many of the components were designed for - heavy trucks. Switching is an extremely hostile environment for equipment. (Ask Ed about how long the track in his switch leads last.) I think that the basic concepts are good and they will get the reliabilty kinks worked out.
dd
dldanceThe short answer is they have more components - thus more items to maintain and more items to break. Long answer is more about the differences in duty/load cycles between locomotives and the applications that many of the components were designed for - heavy trucks. Switching is an extremely hostile environment for equipment. (Ask Ed about how long the track in his switch leads last.) I think that the basic concepts are good and they will get the reliabilty kinks worked out. dd
Aha!
1. Locomotives experience +/- 3G forces with couplings and slack run-ins/outs.. Accelerations of that magnitude will demolish a car or truck. Components and assemblies must be designed to take that.
2. Locomotives flex longitudinally significantly -- the frame is under compression and tension forces and deflects significantly under load. Plumbing and electrical connections, and alignment of rotating components, must be designed to accept that.
3. Locomotives have duty cycles vastly in excess of automotive components. Not too many automotive-type engines, even truck engines, are capable of working at maximum output for more than a few minutes without having component overheating, lubrication starvation, or expansion/contraction issues.
Locomotive design and construction is not a field of endeavor where the inexperienced, incompetent, unwary, or foolish will succeed by accident or luck.
RWM
Railway Man dldance The short answer is they have more components - thus more items to maintain and more items to break. Long answer is more about the differences in duty/load cycles between locomotives and the applications that many of the components were designed for - heavy trucks. Switching is an extremely hostile environment for equipment. (Ask Ed about how long the track in his switch leads last.) I think that the basic concepts are good and they will get the reliabilty kinks worked out. dd Aha! 1. Locomotives experience +/- 3G forces with couplings and slack run-ins/outs.. Accelerations of that magnitude will demolish a car or truck. Components and assemblies must be designed to take that. 2. Locomotives flex longitudinally significantly -- the frame is under compression and tension forces and deflects significantly under load. Plumbing and electrical connections, and alignment of rotating components, must be designed to accept that. 3. Locomotives have duty cycles vastly in excess of automotive components. Not too many automotive-type engines, even truck engines, are capable of working at maximum output for more than a few minutes without having component overheating, lubrication starvation, or expansion/contraction issues. Locomotive design and construction is not a field of endeavor where the inexperienced, incompetent, unwary, or foolish will succeed by accident or luck. RWM
dldance The short answer is they have more components - thus more items to maintain and more items to break. Long answer is more about the differences in duty/load cycles between locomotives and the applications that many of the components were designed for - heavy trucks. Switching is an extremely hostile environment for equipment. (Ask Ed about how long the track in his switch leads last.) I think that the basic concepts are good and they will get the reliabilty kinks worked out. dd
Heck, even the experienced and competent have trouble more often than we'd like. SD50 anybody?
Those gen-set locos have an awful lot of moving parts to do such a small job!
My take on gen-sets is that they are a stop gap measure - a fast way to get Tier II compliant and save a little fuel. Once the automotive industry gets heavy into hybrids, better battery technology will emerge and gen-sets will be replaced by hybrids.
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
Instead of using multiple generator sets, why can't they just go displacement on demand with one larger unit? Wouldn't this accomplish the same basic thing?
Thats an interesting concept if it could be done.
This problem with the gen sets isn't the first time that non-compatability with railroad environments has been a problem. I remember that the Sulzer and even some of the Caterpillar repowering projects didn't work out due to similar reasons.
fredswainInstead of using multiple generator sets, why can't they just go displacement on demand with one larger unit?
More parts to break, a computer to make it all happen. Might work OK in a car, but a locomotive bangs around too much, especially one designed for switching. Maybe we'll see more 710ECOs coming online.
Not sure, but I think the police service Dodge Chargers with the Hemi don't have the MDS system on. Or they are in the shop too much. Meanwhile, the Ford Crown Vics, with basic design from 1979, and incremental improvements, keeps soldiering on. Might not be as fast as the Hemis, but the design is tested and proven.
Mike WSOR engineer | HO scale since 1988 | Visit our club www.WCGandyDancers.com
In classes that I teach - we use railroad locomotives as an example of how to design complex machines for high reliability in a hostile environment. As always, some learn better than others. That is one reason for demonstrators.
Does anyone know what specific components seem to be the least reliable. The traction motors are EMD D77's which were pretty common in SD-40s and as far as I know those aren't an issue. The generators are Cummins inline 6's and that's actually where I'd look to find issues but I don't know. I hope I don't offend any Dodge fans here but Cummins engines are crap. We've used them in the oil field to spin mudpumps and they don't seem to last as long as others that we use such as CAT or Detroit motors. When they do go out, they seem to be complete trash whereas the others are usually rebuildable. Now saying that I'm pretty sure conversions using CAT engines in locomotives have probably had failures too. These companies are more or less using the exact same engines that we'd use in stationary oil field related work. Keep in mind that holding them at full throttle for long periods of time just isn't an issue. They're made to do it. Unfortunately that's not what switching work is. Even if they were road locomotives, their gearing isn't anywhere near optimal to give good TE at high speeds. FWIW: Sometimes we even use large electric GE traction motors which are just rebadged locomotive units!
I'm thinking that while more parts is certainly more room for issues to occur, I have to believe it's more than that. I've seen reports that "they're always breaking" or that "you can't go more than a day without one breaking". If it was merely an issue with more moving parts, the added number of extra parts should correlate with the amount of extra time that issues arise yet it seems to be far greater than that. There must be another reason. What goes out the most on these engines? Is it the diesel engines with mechanical issues? Is it the generators? Is it electronics or wiring? Is it the traction motors? Do they overheat often?
I know we have a few railroad engineers here and I know a couple have run them. Any insight?
I don't know mutch about gensets, but I assume it's all the components that go into one of these engines. I mean have you seen all the stuff that's packed into one of these things?! Just like the crankshaft problems the SD45's had in the begining. The builder's will work out the bugs and I think that these locomotives will turn out great.
The road to to success is always under construction. _____________________________________________________________________________ When the going gets tough, the tough use duct tape.
trainfan1221 They are still relatively new technology, maybe things aren't perfected yet. I know that these are supposed to be one of the big things of the future of railroading. And hybrids, I guess.
Probably because gensets aren't considered up to the task of a regular locomotive, which are more powerful overall. I guess for one of them this was pretty impressive. But keep in mind, 1.8% is a pretty formidable grade if it's a sustained grade.
Ok I see what youe' saying, the genset is made to kick car's around and do odd jobs. Couldn't thay also be used to work a branch line?
bubbajustinOk I see what youe' saying, the genset is made to kick car's around and do odd jobs. Couldn't thay also be used to work a branch line?
Sure. But you might not get much value out of it. The point behind a Gen Set locomotive is that it is optimized for jobs where most of the time there's only low levels of power output needed, whereas a main line freight locomotive is optimized for jobs where most of the time it is putting out continuous high horsepower. You cannot build a locomotive that is equally optimized for both ends of the spectrum, just like you can't expect a Clydesdale to win the Kentucky Derby against a field of Thoroughbreds, or the Thoroughbred to lug a heavier wagon through a muddy field than the Clydesdale can pull.
Switching jobs don't need sustained horsepower output, but use it in spurts followed by periods of low horsepower output or standing still. Instead of having a big prime mover that can deliver its maximum rated horsepower for hours on end without stopping, the idea is to use small engines and just bring them on line one at a time as needed. On a branch line, it is more likely that the locomotive will need to put out moderate to full horsepower for sustained periods. The gen set can do that, but it will burn more fuel, make more emissions, and cost more to build and maintain.
For the same reason, hybrid cars are adapted to city driving, not highway driving. You can of course drive a hybrid from New York to San Francisco, but it will cost you more to do it than the regular car, considering purchase price, maintenance price, and fuel.
fredswainDoes anyone know what specific components seem to be the least reliable. The traction motors are EMD D77's which were pretty common in SD-40s and as far as I know those aren't an issue. The generators are Cummins inline 6's and that's actually where I'd look to find issues but I don't know. I hope I don't offend any Dodge fans here but Cummins engines are crap. We've used them in the oil field to spin mudpumps and they don't seem to last as long as others that we use such as CAT or Detroit motors. When they do go out, they seem to be complete trash whereas the others are usually rebuildable. Now saying that I'm pretty sure conversions using CAT engines in locomotives have probably had failures too. These companies are more or less using the exact same engines that we'd use in stationary oil field related work. Keep in mind that holding them at full throttle for long periods of time just isn't an issue. They're made to do it. Unfortunately that's not what switching work is. Even if they were road locomotives, their gearing isn't anywhere near optimal to give good TE at high speeds. FWIW: Sometimes we even use large electric GE traction motors which are just rebadged locomotive units! I'm thinking that while more parts is certainly more room for issues to occur, I have to believe it's more than that. I've seen reports that "they're always breaking" or that "you can't go more than a day without one breaking". If it was merely an issue with more moving parts, the added number of extra parts should correlate with the amount of extra time that issues arise yet it seems to be far greater than that. There must be another reason. What goes out the most on these engines? Is it the diesel engines with mechanical issues? Is it the generators? Is it electronics or wiring? Is it the traction motors? Do they overheat often? I know we have a few railroad engineers here and I know a couple have run them. Any insight?
I don't know what specific components (or systems, more likely) that are failing.
If the Cummins can tolerate repeated 3G accelerations that are encountered in switching and slack run-ins, they'll probably do just fine. But a locomotive is a lot more than a prime mover and a generator and some traction motors all bolted onto a couple of I-beams with a doghouse at one end for the crew, a fact that has repeatedly been lost on a lot of people who thought they could jump into the locomotive business and beat EMD and GE at the game despite having no experience whatsoever. A locomotive is an integrated system of prime mover and auxiliaries, main generator, switchgear, excitation equipment, controls, bogies, suspension system, draft gear, traction motors, cooling systems, air brakes, and control cab, all of which has to work together in any climate, 24/7/365 hammering itself on bad track with hard couplings, and no maintenance other than a filter change every 90 days and emptying the trash bag in the cab, and putting down a very high level of adhesion onto the rail regardless of how bad the rail condition might be. Fail with one little 10-cent part in one system, and the whole thing stops and waits for a mechanic or electrician. It's as likely that a new company, even one that poached the best people from EMD and GE, is going to jump in and get it right the first time, as it is that I could learn brain surgery from Wikipedia and not kill my first 1,000 patients.
I've purchased switchers for other countries equipped with the Cummins KTTA 19-L1 engine and it has performed well, vastly better than the competition from MTU and Mitsubishi. I don't know how it compares to the Cummins engines used in the U.S. for gen-set locomotives. We used hundreds of Cummins, Perkins, Detroit, and Cat engines for stationary genset applications. They all did well, but the Cats generally lasted longer and cost more to purchase.
So a genset loco is made to bring engines on line when needed. So insted of having a big prime mover putting out a little power and having most of it's potental energy wasted, you can use one or two engines on a genset and have just enough power to do it with.
My guess would be that the computer system used to bring the individual GenSet modules on line is unreliable.
Anybody know if there is a difference in reliability between the NRE and the RP Gensets? Does MP offer a model of their own?
Railpower makes some Road Switcher versions of its gensets, but I don't think there were too many sales. Maybe 20 or so along with about 120 greengoats and kids. They also made some gen sets for the intermodal cranes out in Long Beach, California. I know in their last annual statement to shareholders they talked about having to do a lot of re-work on the green goat series with what I believe were electrical issues. This cost them a lot of money and could be one of the reasons they went into recievership a few weeks ago. Still in business, just under a receiver who will keep an eye on the pennies a bit more closely, or worst case, decide to sell off the technology and any machinery still around.
Most diesel engines are NOT designed to start and STOP all the time. They are designed to run constantly that is why they have the low fuel consumption at idle. Where they are more than likely running into issues is with the Starter motors burning up if they are electric however if they went with Airmotors as long as there is air in the tank they will turn those beasts over. Also the Software to switch them over from one to another at low power could be a huge issue you can not go from full power to shut down without coking up a turbo or scoring a liner on these motors either. Take it from a person that has rebuilt quite a few Cumaparts as they are called in the OTR industry.
First of all I don't design RR equipment ( and don't intend to) but based on other sources of reliability information I would expect the following problem areas (in order):
1) software - lots of things have to line up correctly to switch power sources under load; 2) electronmechanical components such as connectors, switches, relays and transformers; 3) microelectronics stuff; and 4) converted automotive components.
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