Locomotive Questions

[mjchern]

Two Questions:

I've been reading the story in the latest Trains Magazine about the SD70M. One of the improvements over the earlier models is "split cooling." Can anyone tell me exactly what that is?

Also, what does anyone know about GE's radial truck? Last I heard it was experimental, but I don't think I've seen it on regular GE production units except for the AS6000s.

Mike Chern

[mjchern]

Two Questions:

I've been reading the story in the latest Trains Magazine about the SD70M. One of the improvements over the earlier models is "split cooling." Can anyone tell me exactly what that is?

Also, what does anyone know about GE's radial truck? Last I heard it was experimental, but I don't think I've seen it on regular GE production units except for the AS6000s.

Mike Chern

[Anonymous]

This cooling system allowes the turbocharger altercoolers to be cooled down using the same coolant as the engine, but on a separate piping network, separate circulating pump, radiators and fans. The reason for such system was strictly to increase the engine output (+HP's). And in these days the EPA emission regulation for locomotives was not a concern as it's now. Furthermore it been observed that lower the air box temperature offers an improvement in regard to emission reduction as well. So today new and many rebuilt EMD 645 and 710 engines are equiped with four (4) pass aftercoolers instead of a two (2) pass as in the past (better efficiency). BTW the new Metra MP36PH-3S equiped with a 16-645F3B is design as such using a 50/50 water glicol mixture as aftercoolers coolant. The engine coolant is still treated water as before.Don

[Anonymous]

This cooling system allowes the turbocharger altercoolers to be cooled down using the same coolant as the engine, but on a separate piping network, separate circulating pump, radiators and fans. The reason for such system was strictly to increase the engine output (+HP's). And in these days the EPA emission regulation for locomotives was not a concern as it's now. Furthermore it been observed that lower the air box temperature offers an improvement in regard to emission reduction as well. So today new and many rebuilt EMD 645 and 710 engines are equiped with four (4) pass aftercoolers instead of a two (2) pass as in the past (better efficiency). BTW the new Metra MP36PH-3S equiped with a 16-645F3B is design as such using a 50/50 water glicol mixture as aftercoolers coolant. The engine coolant is still treated water as before.Don

[adrianspeeder]

Will the 50/50 water glicol mixture freeze, and therefor have to be drained every time the unit is shut down in cold weather? Thanks.

Adrianspeeder

[adrianspeeder]

Will the 50/50 water glicol mixture freeze, and therefor have to be drained every time the unit is shut down in cold weather? Thanks.

Adrianspeeder

[adrianspeeder]

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Adrianspeeder

[adrianspeeder]

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Adrianspeeder

[jchnhtfd]

Coupla comments... another reason for the split cooling is that aftercoolers, turbochargers, and main engines all like to run at different temperatures if they can. A lot easier with split circuits.

And 50/50 glycol (usually ethylene glycol, but could be propylene...) water mixes don't freeze, and so don't have to be drained. On the other hand... they ain't cheap.

[jchnhtfd]

Coupla comments... another reason for the split cooling is that aftercoolers, turbochargers, and main engines all like to run at different temperatures if they can. A lot easier with split circuits.

And 50/50 glycol (usually ethylene glycol, but could be propylene...) water mixes don't freeze, and so don't have to be drained. On the other hand... they ain't cheap.

[adrianspeeder]

What is an aftercooler? My diesel pickup has an intercooler, it cools air coming out of the turbo before going into the engine. Is that the same thing?

Adrianspeeder

[adrianspeeder]

What is an aftercooler? My diesel pickup has an intercooler, it cools air coming out of the turbo before going into the engine. Is that the same thing?

Adrianspeeder

[Anonymous]

You guys should look at this month's TRAINS. It has a complete discussion on this issue starting on page 34.

LC

[Anonymous]

You guys should look at this month's TRAINS. It has a complete discussion on this issue starting on page 34.

LC

[Mookie]

QUOTE: Originally posted by adrianspeeder

Hey! I got a star!

Adrianspeeder

Congratulations! Welcome to the world of silent conversation!

Mookie

[Mookie]

QUOTE: Originally posted by adrianspeeder

Hey! I got a star!

Adrianspeeder

Congratulations! Welcome to the world of silent conversation!

Mookie

[Anonymous]

QUOTE: Originally posted by adrianspeeder

What is an aftercooler? My diesel pickup has an intercooler, it cools air coming out of the turbo before going into the engine. Is that the same thing?

Adrianspeeder

Adrian, Yes they do the same thing but an aftercooler uses the coolant to cool the compressed air and an intercooler uses the air passing thru the radiator to cool the air. [^]

[Anonymous]

QUOTE: Originally posted by adrianspeeder

What is an aftercooler? My diesel pickup has an intercooler, it cools air coming out of the turbo before going into the engine. Is that the same thing?

Adrianspeeder

Adrian, Yes they do the same thing but an aftercooler uses the coolant to cool the compressed air and an intercooler uses the air passing thru the radiator to cool the air. [^]

[gwjordan1950]

IfSince your on the subject of coolers. The trucking industry on their engines, mostly large c.i. displacement, has both. The intercooler is along side the radiator. You might think that the whole area is radiator and coolant. It is not . the one side is air flow off of the turbo. it then hoes out to to intake manifold where it goes into the aftercooler. This cools the air down to where it is a reasonable temp.to go into the cylinder for mixing, as the fuel is being atomizing thru the injectors for combustion. The temp of the air coming out of the turbo, if being under a heavy pull can be in excess of 1200 degrees!! that is the reason for inter and after cooler4s. I don't understand why the railroad industry is just now switching over to either ethylglycol or other types of coolant for their engines. They run so much cooler with a 50/50 mix of water and coolant. this is My opinion!!!!!!

[gwjordan1950]

IfSince your on the subject of coolers. The trucking industry on their engines, mostly large c.i. displacement, has both. The intercooler is along side the radiator. You might think that the whole area is radiator and coolant. It is not . the one side is air flow off of the turbo. it then hoes out to to intake manifold where it goes into the aftercooler. This cools the air down to where it is a reasonable temp.to go into the cylinder for mixing, as the fuel is being atomizing thru the injectors for combustion. The temp of the air coming out of the turbo, if being under a heavy pull can be in excess of 1200 degrees!! that is the reason for inter and after cooler4s. I don't understand why the railroad industry is just now switching over to either ethylglycol or other types of coolant for their engines. They run so much cooler with a 50/50 mix of water and coolant. this is My opinion!!!!!!

[CSSHEGEWISCH]

Railroads don't use glycol/water mix for a number of reasons. Cost is one factor. Antifreeze isn't cheap and locomotive cooling systems are huge. Another is the possibility of bearing damage from coolant leaking into the crankcase oil if glycol is in the coolant mix.

[CSSHEGEWISCH]

Railroads don't use glycol/water mix for a number of reasons. Cost is one factor. Antifreeze isn't cheap and locomotive cooling systems are huge. Another is the possibility of bearing damage from coolant leaking into the crankcase oil if glycol is in the coolant mix.

[oltmannd]

QUOTE: Originally posted by CSSHEGEWISCH

Railroads don't use glycol/water mix for a number of reasons. Cost is one factor. Antifreeze isn't cheap and locomotive cooling systems are huge. Another is the possibility of bearing damage from coolant leaking into the crankcase oil if glycol is in the coolant mix.

...and one other thing. You don't get as much cooling capacity out of antifreeze/water mixture as you do with straight water. Although the boiling point is raised and you can carry a higher temp differential, it's more that offset by the mixture's lower specific heat and lousy heat transfer properties. At Conrail, we looked pretty hard at testing some antifreeze (propylene glycol) in some EMDs and thought we could get away with the reduced cooling capacity (the cooling systems on locos are designed for the desert SW - the NE isn't as hot), but the chance of the coolant getting into the crankcase was just too scary.

[oltmannd]

QUOTE: Originally posted by CSSHEGEWISCH

Railroads don't use glycol/water mix for a number of reasons. Cost is one factor. Antifreeze isn't cheap and locomotive cooling systems are huge. Another is the possibility of bearing damage from coolant leaking into the crankcase oil if glycol is in the coolant mix.

...and one other thing. You don't get as much cooling capacity out of antifreeze/water mixture as you do with straight water. Although the boiling point is raised and you can carry a higher temp differential, it's more that offset by the mixture's lower specific heat and lousy heat transfer properties. At Conrail, we looked pretty hard at testing some antifreeze (propylene glycol) in some EMDs and thought we could get away with the reduced cooling capacity (the cooling systems on locos are designed for the desert SW - the NE isn't as hot), but the chance of the coolant getting into the crankcase was just too scary.