GEVO ?

[mackb4]

 A diesel locomotive can still be operated without an operable turbo,but will of course have less h.p. .

 Most GE locomotives have boost from the turbo from notch #5 to #8.

 You can really hear the difference in the loco. cab when you go from #4 to #5.

 And a bad turbo will sometimes make a thumping noise and a shake that can be felt.   

[beaulieu]

blue streak 1

Can GEVOs be run with the turbocharger cut out?? If so at what HP?

 

I might run but it would not be legal as it would not meet emissions regulations. You won't see any non-turbocharged EMDs built anymore either.

 

UP has found 194 GEVOs that will need their turbos replaced so far, with more to be inspected.

[mackb4]

  The memo we got here on the Pokey stated that GE claims (2) GEVO locomotives suffered turbocharger failures that resulted in the turbine leaving the turbocharger housing than exiting the locomotive body.

 We are now advised to not walk past a GEVO unit on the walkway while the engine is loading in #1 notch or higher.

 This included all NS 7500 and 8000 series units.

[creepycrank]

Turbos typically increase power over naturally aspirated by about 50 to 100%. Four stroke engines are supposed to be able to limp along with a failed turbo but you have make sure its not leaking oil into the intake. I don't think the computer control would let the engine get off idle with a vacuum in the engine intake manifold. I think that since the turbos come apart at maximum power that they could derate the engines to about 3800 hp @ 900 rpm will reduce the temperature and flow to the turbo well below detonation speed. There is a Electromotive (without the dash) company that makes data loggers that monitor turbo speeds and I seen them on the large CAT engines. Computers now serve as a sort of on board engineer with his clipboard so something like that could cut back the power just before destruction.

[MJChittick]

blue streak 1

Can GEVOs be run with the turbocharger cut out?? If so at what HP?

Not effectively.  One would likely lay down more smoke than an old Alco 244!

[blue streak 1]

Can GEVOs be run with the turbocharger cut out?? If so at what HP?

[wabash1]

SSW9389

Yesterday the wife, grandaughter and I took one of our cats over to the county clinic to get its shots. At the Kentucky Street crossing here in Shelbyville sat an NS work train in the siding. An NS GEVO #7552 was power for this nine car work train. I have to wonder if the unit has been downgraded to work train service while this turbo issue is being worked out. It seems kind of strange to have a high capacity, high dollar unit on a nine car work train, but it makes better sense to use it for that than to park it.  

Ed in Shelbyville

That is not the reason at all, The NS is taking engines out of service as needed to check  them out the reason for this engine on a work train is it was probley the only one around free for duty, and the air condition is nice for the crew. on the NS it dont matter what engine is on a work train  and ive seen dash 9s or sd 70 on work trains while heavy thru frieght recieve a couple of sd40 and maybe a gp 38 to work with a sd 60. the ns only rule right now is that if you have a gevo junk GE engine you are not to walk out to other units while engine is loading.  Other wise its buisness as usual.

[aut1rml]

I agree with you Pete. We also had a rash of Mack turbo failures years ago at big brown. Now a days it is IHC variable turbos that fail due to coked up unison rings,but they are not blowing apart. Cat quit the truck line to concentrate on the expanding need for earth moving equipment in places like China. These engines need not meet the U.S. EPA standards not to blow smoke on the highway.

[creepycrank]

Its been fun to speculate about all this but where is GE's normally hyperactive publicity department in all this. You railroad personnel should know this but as far as I know all previous railroad turbo disintegration were contained by the housing letting the rebuilders to sort it out.

[blue streak 1]

creepycrank

None the less blue streak layout the engineering process necessary to solve the problem. GE will have to consider a redesign of the casing or a scatter shield before the railroads install their own. The present design must be pretty close to the ragged edge to require very careful manufacturing methods.

If it is the shaft that is failing-----WHY is it failing?  If the shaft is not robust enough it may require a thicker shaft. Then the bearings, wheels, turbines, lubrication, etc may all have to be redesigned.

If a shaft of different metal with the same dimensions can be used ---stilll all the above items will need to be considered but not necessarily required. Intermetal interactions need to be considered ( extreme example not applicable here copper--aluminum)

[SSW9389]

Work train GEVO July 26, 2009. It rained last night and the fog hadn't burned off yet when the photo was taken.

 

[SSW9389]

Yesterday the wife, grandaughter and I took one of our cats over to the county clinic to get its shots. At the Kentucky Street crossing here in Shelbyville sat an NS work train in the siding. An NS GEVO #7552 was power for this nine car work train. I have to wonder if the unit has been downgraded to work train service while this turbo issue is being worked out. It seems kind of strange to have a high capacity, high dollar unit on a nine car work train, but it makes better sense to use it for that than to park it.  

Ed in Shelbyville

[edbenton]

No it is simple FORCE appiled.  Most Turbochargers and GE uses a true one all the are is a shaft a compressor wheel and a Turbine wheel mounted on a set of bearings with an oil supply mounted in an extremely close tolorance HOUSING.  Now the exhaust from the engine hits the turbine wheel and spins it and on an OTR truck motor they can spin up to 70k-100K rpm I imagine that GE's is in that speedrange.  I had one shaft failure while driving under full load The turbine housing section made out of cast moly steel went THRU the hood of my 1997 Peterbilt 379 like it was not even THERE leaving a 3 foot hole in the side of the hood.  The compressor section made from Alumimun took out the Oil filter mount and oil cooler with the shrapnel it had made.  All the shop said is what the hell happened CAT was like we have never seen one let loose like that.  They found a sliver of O-ring blocking the feed line to the turbo and it had gotten hot and eventually crackd off.  The thing had run like that for close to 500K before letting loose but when she did LOOK THE HELL OUT.

 

If it is the shafts that are failing there is only one way to get rid of the problem replace the whole assembly.  Turbos have to be balanced as a rotating unit do you want something out of balance at 70K RPMs I think not they would tear themselves apart faster than for us WW2 buffs the Japanesse planes BLEW UP.

[creepycrank]

None the less blue streak layout the engineering process necessary to solve the problem. GE will have to consider a redesign of the casing or a scatter shield before the railroads install their own. The present design must be pretty close to the ragged edge to require very careful manufacturing methods.

[BaltACD]

blue streak 1

If I were an engineer at GE here is how I would proceed with solving this problem.

1. Request all operating RRs to temporarily park as many of the affected units as possible and bring other units back in service ( thank goodness for the recession).

2. Has this turbos been installed on other units in the past?

     A. Are they being used differently.  a. different electronic programing  b. higher exhaust temps   c. higher airflow inlet or outlet.    d. other imput or output differences   e. any upgrades for this application?

     B. Have these units failed in the same way on other types of locos?

3. A new turbo what are the design differences?

     A. Are all failures the same?

     B. Fatigue analysis and testing of critical parts?

     C.. Why is containment casing not holding together when a failure? (safety item)

     D. If failed part made by more than one vendor is it both vendors or not?

     E. Get metalurgic analysis of failed part

     F. Redesign turbo if necessary.

     G. Replace suspect turbos.

Although this is only a partial flow for solving this problem I hope you get the idea?

Beauleiu has already stated the the failures have been isolated to a shaft that has been supplied by two vendors, one of which is below standard.  I don't know how detailed the GE assembly records are or if they can isolate which engines were constructed with the bad shaft.

[blue streak 1]

If I were an engineer at GE here is how I would proceed with solving this problem.

1. Request all operating RRs to temporarily park as many of the affected units as possible and bring other units back in service ( thank goodness for the recession).

2. Has this turbos been installed on other units in the past?

     A. Are they being used differently.  a. different electronic programing  b. higher exhaust temps   c. higher airflow inlet or outlet.    d. other imput or output differences   e. any upgrades for this application?

     B. Have these units failed in the same way on other types of locos?

3. A new turbo what are the design differences?

     A. Are all failures the same?

     B. Fatigue analysis and testing of critical parts?

     C.. Why is containment casing not holding together when a failure? (safety item)

     D. If failed part made by more than one vendor is it both vendors or not?

     E. Get metalurgic analysis of failed part

     F. Redesign turbo if necessary.

     G. Replace suspect turbos.

Although this is only a partial flow for solving this problem I hope you get the idea?

[oltmannd]

tomikawaTT

Has anyone considered establishing a maximum operating time for railroad turbochargers?

Yes. Generally, the are rebuild when the rest of the engine is rebuilt. They'll hang in there as long as the engine main bearings - as long as nothing external get them.

[bubbajustin]

Ok, that makes scince!

Thanks!

Justin

[beaulieu]

For reference GE reportedly had two suppliers for the affected part, the failing parts were all made by one of the suppliers. I have seen no indication that each supplier provided the same number of parts.

[creepycrank]

bubbajustin

When a turbo goes, does it completely stop the locomotive from moving? Or can it still move, but with less horsepower? What does it look like when one blows?

Thanks for answering my questions!

Justin

No. If failed turbo took out the bearings and shaft seals all that lube oil will get into the still running engine and the engine can runaway on its own oil until it comes apart.

[locoi1sa]

 When a turbo fails in service it is usually catastrophic. Depending on the application and configuration of the engine one type of failure is more damaging than another. With most turbo failures there will be a massive amount of oil ingestion into the after cooler if equipped or worse right into the intake manifold and get burned uncontrollably by the engine until further damage is done. A compressor wheel failure will flood the air intake with metal fragments. A turbine wheel failure will cause an almost suffocation of the inlet air and exhaust system and is typically seen as tremendous amount of smoke if the engine keeps running. Some turbos are cooled by the cooling system and any one of these failures can cause coolant leaks and contamination of the oil and air intake.

 Way back in diesel school I saw a movie put out by Detroit diesel ( the little brother of EMD). They had an inline 6-71T running on a dyno with no air filter. At 2000 RPM under load a person through a table spoon of fine dirt into the air intake and the whole side of the engine exploded with a great fire ball and shrapnel flying in every direction. Even the camera was destroyed.

 With out knowing the type of failure its just a guess on whats happening with the GEVOS. With the high RPM of a turbo and the tremendous strain of the compressor and high heat of the exhaust side any type of failure can be instantaneous and any shut down safety appliance will be too late to be effective. When a Cat C15 diesel engine is working under load the turbo can be spinning at 60 to 70 thousand RPM. Exhaust temps can climb to well over 900 degrees and boost pressures can be as high as 40 PSI. Running trucks on the chassis dyno I have seen the turbos glow cherry red and some have turned bright cherry almost white.

     Pete

[bubbajustin]

When a turbo goes, does it completely stop the locomotive from moving? Or can it still move, but with less horsepower? What does it look like when one blows?

Thanks for answering my questions!

Justin

[oltmannd]

JayPotter

Paul_D_North_Jr

Some failure modes give advance warning and can be detected in advance; others - like metal fatigue and breakage of the blades from the shaft, etc. - may happen in just seconds, and progress rapidly and catastrophically.

I suspect that if a given component fails, via either of those two modes, more frequently than it is expected to fail, the railroad and the manufacturer will (1) notice the frequency, (2) diagnose the cause, and (3) take corrective action.

 

In the good old days, if it was EMD, first EMD would say "what problem?" Then, when you showed them, they'd say, "You must be doing something wrong because it's not a problem with our product." Then when you became insistent, they would say, "Oh, that problem. We know about it and are testing a fix on road XYZ."

[caldreamer]

 Please remember that other locomotives have had major problems that were overcome.  The one that comes to mind is the SD45's 20 cylinder 567 prime mover.  A very popular, productive and  long lived engine once the problem was resolved.

[BaltACD]

tomikawaTT

Back when I was bending wrenches on Sams airborne assets, turbos were a time change item - if it had XXX flying hours, it came off and was replaced by a like serviceable item from stores.  Waiting until it blew up wasn't a viable option if the failure was likely to occur five miles above the Pacific and a thousand miles from the nearest adequate runway.

Has anyone considered establishing a maximum operating time for railroad turbochargers?

Chuck {MSgt(ret) USAF)

The rate at which GEVO's appear to be blowing Turbos would give these problems the term 'Infant mortality' when considered in the life and service span of locomotive.  The Class I carriers desire that locomotives only require fuel, sand, toilet cleaning and window washing as the only maintenance between the required 92 day inspection intervals.  I would expect that the normal service life of turbos is expected to be the service life of the prime mover itself. 

There is a big difference in spending taxpayers money for something that can fall out of the sky and spending private money on a failure that doesn't fall out of the sky, just creates a problem that had to be worked around and solved, as in moving the train that has had an engine failure to it's final destination.

[JayPotter]

Paul_D_North_Jr

Some failure modes give advance warning and can be detected in advance; others - like metal fatigue and breakage of the blades from the shaft, etc. - may happen in just seconds, and progress rapidly and catastrophically.

I suspect that if a given component fails, via either of those two modes, more frequently than it is expected to fail, the railroad and the manufacturer will (1) notice the frequency, (2) diagnose the cause, and (3) take corrective action.

 

[Paul_D_North_Jr]

Some further thoughts / questions -

Don't most or all of these GEVO units have the ''satellite-phone home'' system to report on and montior their condition in 'real time' ?  Wouldn't that provide a way to keep track of how they're doing ?

Plus, once the 'likely suspects' are identified - can they be watched more closely, pending or deferring the need for actual replacement ?  Does anyone know the actual failure mode for these - is it fatigue, wear and bearing, soft metal, etc. ?  Some failure modes give advance warning and can be detected in advance; others - like metal fatigue and breakage of the blades from the shaft, etc. - may happen in just seconds, and progress rapidly and catastrophically.

I'm not a mechanical engineer - so this is subject to correction - but aren't some things like that monitored by bearing temperatures, vibrations, and periodic spectrographic analysis of the lube oil to see what's wearing out and leaving specific metal alloy traces in the oil ? 

I'd guess that on a 2 million dollar loco, a turbo is worth between 50,000 and 200,000.  To avoid having to replace that unnecessarily, would surely justify more intensive inspections, installing more sensors for  vibration or temperature, more frequent lube oil tests, etc., up to a point. 

- Paul North.

[JayPotter]

Paul_D_North_Jr

Plus, otherwise, why the need 'inspect' them ?  Why not just pull them all, that were manufactured by the XYZ Turbo Co. and / or installed between date-1 and date-2 ?

Potentially defective turbochargers can be indentified by their serial numbers, which are documented for units that have never had their turbochargers replaced.  However if a unit has had its turbocharger replaced at some point in the past, the replacement turbocharger needs to be inspected to determine its serial number.

[oltmannd]

Paul_D_North_Jr

Anybody know who made the turbos - could it have been GE itself

Way back when, Elliot made the turbos for GE engines.  GE makes them now.  GE should have quite a bit of experience with gas turbines given their position in the jet engine business.