How does a railroad know when to rebuild a locomotive?

[88gta350]

What is the criteria for when to rebuild an engine? Is it miles? Hours of service? Years/months in service? Or is there a set of performance criteria that the engine must maintain or be rebuilt (horsepower, torque, etc)?

[Mikeygaw]

was a nice little topic while back... cant seem to find it though...

if i remember, the mileage was every 500,000, 1 million or 1.5 million miles with a max of 30 years... i think

[csxengineer98]

after a wreck or when the rust starts to eat holes through the cab to the point that ductap wont keep the wind out of the cab....only then will the railroads even think about sending it to the shop for a complete rebuild..hahahahah
csx engineer

[Junctionfan]

When the railroads are too cheap to spend money on modern ones....hahahaha

[csxengineer98]

QUOTE: Originally posted by Junctionfan

When the railroads are too cheap to spend money on modern ones....hahahaha

then they are too cheep to spend the money on new ones...or dont have the money to rebuild...they just get a LT&E loco or some other rebuilder...csx engineer

[Randy Stahl]

Most of the time a single locomotive isn't singled out to be rebuilt. It will be a class of locomotives that are otherwise worth while machines. A group of locomotives must still have utility. Most locomotive components have been changed out more than once already by the time a class rebuild is done. EMD recommends that major components :power assys, wheels, traction motors,air compressors,pumps,are changed out at regular intervals. I think I remember that EMD says the 645E3 needs to be changed out every 20 years.
Many times a class of locomotives is rebuilt to take advantage of new technology, stuff that wasn't available when the locomotive was built, like bolt on adhesion systems etc.
The improvements in performance adding this new tech gear makes rebuilding the machines very competative with buying a new locomotive.
Randy

[Anonymous]

QUOTE: Originally posted by csxengineer98

after a wreck or when the rust starts to eat holes through the cab to the point that ductap wont keep the wind out of the cab....only then will the railroads even think about sending it to the shop for a complete rebuild..hahahahah
csx engineer

Yeah, but they still won't send it until it dies in line of road or some critical part falls clean off...

LC

[csxengineer98]

QUOTE: Originally posted by Limitedclear

QUOTE: Originally posted by csxengineer98

after a wreck or when the rust starts to eat holes through the cab to the point that ductap wont keep the wind out of the cab....only then will the railroads even think about sending it to the shop for a complete rebuild..hahahahah
csx engineer

Yeah, but they still won't send it until it dies in line of road or some critical part falls clean off...

LC

thats where a hammer and ductape come in...
csx engineer

[oltmannd]

What do you mean by "rebuilt"? Very few units are totally rebuilt but just about all do get their components overhauled during their lives.

Railroads will typically schedule components to be rebuild based on when inspections tell them the parts are worn out. For example, the RR will monitor the condition of the power assemblies and bearings on a given class in their fleet. They can see the wear rate by visual inspection, so they will be able to tell that that the power assemblies will need replacing in the 5th year. They'll build a budget and back shop program around these findings and then actually do the work as units fall out of service or they find worse than average units in the fleet. While the locomotive is getting new power assemblies, other overhaul work will usually be done (budget permitting!) to allow the locomotive to stay out of the backshop for another 5 years. For example, the trucks, main generator bearing and aircompressor may also be overhauled.

Sometimes traffic conditions or budget constraints will delay an overhaul program. And the RR will cross their fingers that most of the units will hang in there another year without sending power assembly parts thru too many turbos.

[88gta350]

I was thinking of the engine itself, rather than the whole locomotive. Thinking of a locomotive as just a big car, systems will be replaced as they break/wear, or preventative maintance will be done to replce/servce parts before they fail, but at what point does the engine itself (block, pistons, etc) need rebuilt? How many miles does the typical locomotive run before the engine just can't go any longer, despite maintanance and repairs?

[SSW9389]

Do the railroads still use spectrographic analysis of oil samples to see what metals are showing up in the engine oil? I've read that this is used to tell when a locomotive is due for shop time.

[M636C]

The last of the old State Government Railways, Queensland Rail, certainly did spectrographic analysis in the 1970s, as did most of the systems. Now the efficient private railways in Australia have lost or sold off the big workshops that had the scientific equipment (except Queensland).

However, the major work is contracted to the locomotive builders and I imagine they still use oil analysis along with the other diagnostic techniques to determine what work is needed.

Spectrum analysis did tell you what types of metal were in the oil - high copper meant bearing wear, other metals would indicate piston liner and ring damage.

Peter

[csxengineer98]

QUOTE: Originally posted by SSW9389

Do the railroads still use spectrographic analysis of oil samples to see what metals are showing up in the engine oil? I've read that this is used to tell when a locomotive is due for shop time.

i dont know if csx uses spectrographic analysis..but they do have some kind system... they have bar code tags on the locomtives..and i have seen in some of the shop areas bottles that have a bar code that i guess matches the bar codes on the locomtives... im guessing for some kind of oil testing..
csx engineer

[Anonymous]

When the connecting rods and pistons come out of either the cylinder heads or the base pan,followed by copious amounts of crankcase oil[;)], just like a car would[:-^]. LOL

[oltmannd]

Spectrographic analysis of oil will tell you when you have a BIG accute problem, not generally when the engine is worn out. You do that by direct inspection. On an EMD you can see the rings directly thru the liner ports and they a have grooves on them to judge the wear. On a GE, you can stick a boroscope down the fuel nozzle hole and get a look at the liner walls.

Oil analysis mostly tells you when to change the oil and it you have a water leak some where. Both extremely valuable pieces of information.