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BNSF Executive SD70MAC Rebuild Program?

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Posted by NorthWest on Sunday, May 29, 2016 7:50 PM

BNSF has plenty of far better local power. It seems that effectively new high-horsepower ACs would be better in bulk service than any other role, but there are probably good reasons for the change. I'd like to know them.

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Posted by NorthWest on Monday, May 30, 2016 12:20 PM

Although, here's one as a one-unit-wonder on a local:

http://www.railpictures.net/photo/578265/

Tongue Tied

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Posted by Entropy on Tuesday, May 31, 2016 7:21 AM

beaulieu

At some point in the production of SD70MAC locomotives the Diesel Engine switched from a 710G3B-EC engine to a 710G3B-ES engine. One of the notes in my EMD SD70MAC shop manual says that locomotives equipped with the early EC series engine has two water pumps, one supplies water to each bank of cylinders of the diesel. The newer ES version also has two water pumps, but one pumps water to both banks of the diesel, while the other pumps water to the turbocharger aftercooler. And the plumbing arrangement is very different. I suspect that only SD70MACs with the ES engines are being upgraded. It is also being reported that they are officially being rated at 3999 hp. to keep them out of the mainline freight pool.

 

 

What you're describing is SLAC or by other companies terminilogy SCAC. Seperate Circuit Aftercooling. This became utilized for Tier 1 emissions in order to lower the intake air temperature, lower NOx levels; but resulted in higher engine performance, and lower fuel consumption. 

Many on here are familiar with the use of aftercooling, however for others, typically an aftercooler will use a water connection with the radiator water, this is 'JWAC' Jacket Water After Cooling. For 'SLAC' by giving the aftercooler its own water pump and radiator section, the aftercooler temperature rises at its own rate rather than engine temperature and above, allowing higher amounts of heat absorbtion. 

When those production changes were made on the SD70MAC, for JWAC/SLAC was covered in a previous post in this thread. 

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Posted by VGN Jess on Tuesday, June 21, 2016 1:31 AM
I though the "e" stood for: electrical enhancements
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Posted by SooBoy61 on Monday, July 18, 2016 12:46 AM

More news out of Progress Rail Tacoma regarding the BNSF SD70MAC upgrades.  Although I wasn't witness to the beginning of the first units receiving their upgrades it's certain the latest units are getting a complete overhaul.  They have had their prime movers, alternators, radiators, turbos, air compressors, inverters, air reserviors and air intakes removed.  Not much remaining above the frame except the cab and the radiator hood.  More units have been added to the stable so it appears that BNSF/Progress Rail has decided to go ahead with this full bore.  The latest units to arrive are 9729, 9768, 9771 and 9772 which brings it to about 20 units that have either been completed or in progress.

As an added twist there has been one other recent arrival that might spark some interest.  Sitting with the SD70MA0C's is BNSF 200, the first of the BNSF SD75M's.  One can only assume BNSF/Progress Rail plans on doing something with these.  It remains to be seen whether they will be overhauled as is or be converted to SD70/75MACe's.  Between the SD7M/SD75I's BNSF has probably about 90 of these in storage accounting for those that went to NS.

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  • From: NW Wisconsin
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Posted by beaulieu on Monday, July 18, 2016 2:15 PM

SooBoy61

As an added twist there has been one other recent arrival that might spark some interest.  Sitting with the SD70MA0C's is BNSF 200, the first of the BNSF SD75M's.  One can only assume BNSF/Progress Rail plans on doing something with these.  It remains to be seen whether they will be overhauled as is or be converted to SD70/75MACe's.  Between the SD7M/SD75I's BNSF has probably about 90 of these in storage accounting for those that went to NS.

All the surviving units of Santa Fe's first order for SD75Ms (ATSF 200 - 250 later BNSF 8200 - 8250) have gone to Progress Rail. Progress Rail will sell or lease them to whom ever needs them, BNSF no longer needs them.

 

 

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Posted by SooBoy61 on Thursday, August 11, 2016 6:21 PM

Curious to know if BNSF owned the SD75M/I units or if they were leased?  Back in 2013 BNSF sent a bunch of these to NRE but since then a good number of those have shown up in storage in BNSF yards (mainly Galesburg and Minneapolis).  All of these have all their BNSF markings with the BNSF 200 series numbers.

Also, it appears that Progress Rail has intentions of doing a more than a one unit rebuild as 3 more SD75M's have arrived in the past week (BNSF 201, 202 and 204).  With the ongoing rebuild of the SD70MAC's, the AC44C4M program, and obtaining mostly new AC power (ET/ES44C4's) BNSF seems to have made a strong commitment to AC power.  Could it be in the cards to have Progress Rail rebuild the SD75M/I's to SD70MACe's for BNSF? 

 

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Posted by NorthEast on Sunday, July 30, 2017 8:41 AM

New to this site and the forums here.  I am doing so research on the SD70MAC series of locomotives and was curious if there have been updates, insight, information on the BNSF rebuild program since last year (July 2016 post).

 

Specifically i am curious if anyone has update or confirmation that the program did focus on those ES units and not the EC older units.  I think the EC units were 1994-96 vintage and ES 1997+ vintage.

Are there other threads you all have written participated in which covers the SD70MAC's?

thanks.

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Posted by kgbw49 on Sunday, July 30, 2017 5:50 PM

 NorthEast, if you go to

www.railpictures.net

and search on SD70MACe you should bring up quite a few photos of SD70MACe units.

Some of the captions on the photos list the original number of the rebuilt locomotive, so from that information you may be able to back in to which series have been getting rebuilt.

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