Question for Rich Melvin

Maxrailroad posted:

Hey Rich, 

I got a question. A while ago you posted on a topic about a NS train on fire that it was a super charger that blew. You said that it may have caused a runaway because it is hard to seal of the air in a diesel. So my questions are, 

1) How would sealing off the air help?

Without air/oxygen, then there can be not combustion/fire.

2) If the air couldn't be sealed off and the train became loose, how would they stop it?

You must have misunderstood,  Rich was NOT referring to a "run-a-way" train, but the diesel engine (prime mover) inside the engine room, was "running away" or "uncontrolled over-speeding". Thus, if it had been possible to close off the air intake, then the diesel engine would have slowly died. 

Thanks,

Max

Hot Water and Wyhog explained it very well. Thanks, guys!

Is there a fuel shut off valve ??  The engine couldn't run long on just turbo oil could it ??

jim pastorius posted:

Is there a fuel shut off valve ?? 

Yes, there is an "overspeed trip" mechanical mechanism, the locks the fuel injectors off the camshaft, on EMD engines. I can't remember how the GE engine o\"overspeed trip" works.  

The engine couldn't run long on just turbo oil could it ??

You would be amazed how long a diesel engine, especially a railroad locomotive diesel engine, will run on just lube oil, so long as the is combustion intake air, or until the engine throws itself apart, i.e. until the oil is all used up.

I once saw a GE diesel run for almost 20 minutes on just lube oil being sucked into the engine past a blown turbo shaft seal. The engineer had hit the emergency fuel cutoff early in the event, but the "fuel" being sucked past that seal was enough to keep her going for 20 minutes. It never had enough oil flow to over speed the engine, but the towering column of smoke made it look like a steam locomotive.

Here's an example. It starts out with the big tower of smoke because the mixture is way too rich. There is way too much fuel (lube oil) going into the engine for the amount of air being moved through it. Towards the end the air fuel mixture leaned out a little as the flow of oil slowed. It finally reached a point where the mixture was right and the exhaust gases burst into flame. The flames remained until all the lube oil was burned up.

Thanks for the replies. So what you are saying is that the train will not become a run away, but the engine will just run uncontrollably. 

This is why I really like this forum. I can post any train question I have and am sure to get an answer. Everyone here is just so train smart. Rich, hats off to creating the best forum out there.

One more question for Rich. When you were pulling out of Steamtown on 9/5/15, did you hear someone yell, "I LOVE YOU RICH MELVIN"? That may have been someone I am very close too...

Rich hears that all the time. An NS engineer told me that women love railroaders. He laughed and said,"They think we have money".

jim pastorius posted:

Rich hears that all the time. An NS engineer told me that women love railroaders. He laughed and said,"They think we have money".

Lol! We spend all the money on trains though.

OK, poor seals ??   I know all about them. So why are there more GE smokers than EMD  ??  I read that there was a design difference.

jim pastorius posted:

OK, poor seals ??   I know all about them. So why are there more GE smokers than EMD  ??  I read that there was a design difference.

Yes, there is a MAJOR design difference. GE and Alco locomotives use 4-stroke cycle diesels, while EMC/EMD has always, until recently, used 2-stroke cycle diesel engines. With the 4-stroke cycle design, there can be serious "turbo-lag" which results in smoke during throttle increases. The EMD 2-stroke cycle design has gear driven blowers, for the lower horse power units, or a gear driven thru an overrunning clutch design turbocharger, resulting in generally no turbo-lag and no smoke.

I knew there was a difference but had forgotten it. Now with the new EMDs running 4 cycle engines I wonder how there blowers will be hooked up. Not too much info out there yet on these new engines. But, I will say, you would think GE engineering would try to improve their seal problem. There are various ways but  maybe $$ is involved.

jim pastorius posted:

I knew there was a difference but had forgotten it. Now with the new EMDs running 4 cycle engines I wonder how there blowers will be hooked up.

They do not use "blowers" but twin turbochargers, and with modern day computer controlled fuel management systems, the old days of "turbo-lag" are pretty much gone.

Not too much info out there yet on these new engines. But, I will say, you would think GE engineering would try to improve their seal problem. There are various ways but  maybe $$ is involved.

GE did indeed solve the Turbo seal" issues, as well as computer controlled fuel management in order to reduce "turbo-lag" smoke.

Maxrailroad posted:

One more question for Rich. When you were pulling out of Steamtown on 9/5/15, did you hear someone yell, "I LOVE YOU RICH MELVIN"? That may have been someone I am very close too...

Unfortunately, with all the noise the 765 makes, I did not hear that. Evidently I missed a special moment. 

Now...and this is very very important...let's just keep this between us, OK? Please don't tell The Lovely and Gracious Linda (my lovely wife of 46 years.  )