I remember reading in the Trains SD90MAC special issue a number of years back, with the text reading something in the lines of “The 4 stroke H series engine is the meanest gruffest sound in modern railroading”.
I remember ONCE hearing a true AC6000 load up and the sound was pretty darn mean. I have yet to hear an 90MAC load up.
I have a few questions:
I’ve read loosely that all AC6000 have been downrated to 4400hp. Is this true?
Living in Los Angeles, what are the odds that a true 90MAC will pass through?
Are there even any true 90MACs doing urban service (in LA)?
Are there many 9043MACs converted to H series engines?
What do you guys think of their sound?
I work next to the old SP main line just north of the Taylor yard. I work a later night shift so I hear many different sounds that I never really experienced being a younger railfan with little time to do some dedicated trainspotting. Earlier in my railfanning history, I used to always search for the new stuff, like the Dash 9’s which of course was rare for SP territory in LA, so my only choice would be BNSF, which I had little access or time to visit. But now, I see myself looking for the older/louder SD45’s, SD40’s and Dash 8’s that are getting harder to find in the sea of UP’s SD70Ms.
Anyway, i’ve grown to like GE’s 4 stroke pulse note, but have yet to really see or hear any big 6000 hp locomotives at my place of work. I’d really like to hear a true 90MAC. Can anyone give me any advice or news regarding the 6000hp units, mainly how to differentiate a de-rated AC60 from a true one, and an upgraded 9043MAC?
OK, somebody should answer this, but my experience with AC6000 locomotives is gained in North West Western Australia, where there are plenty of Dash 8s, Dash 9s and a few AC6000s but no SD90s of either type (although SD70ACes are expected very soon)
In Australia, the AC6000s are still running at 6000 HP.
The AC6000 has a deeper more “hollow” sound than the Dash 8 and since they usually run together, is the predominant sound heard.
I don’t think any SD9043 has ever been upgraded to an H engine. I think one may have been converted from an H engine to a 710.
I understand that a number of UP SD90MAC-H are coming off lease any time now so the chances of seeing one anywhere are getting less.
You can tell a true AC6000 from one with a FDL engine because the HDL engine has two turbochargers side by side, resulting in twin stacks side by side.
If the locomotive is just downrated by limiting the top speed of the HDL engine, there would be no way of telling that I can think of.
I would figure you have a fair chance since last I knew UP used them in intermodal and general frieght service. (Though I saw 5 of them in coal service in the PRB though back in 03 so maybe not)
Do you mean switching? Would have to doubt it. A bit to much power to be economical.
Don’t believe a single one has been uprated. Why would they do that when they are getting rid of the H-engine ones in about 2 years
I talked to a UP engineer around the time they were built and he said when they first came out they had problems(can’t remember what,it was 6 years ago).UP started downgrading SD90MACs to SD90/43MAC and AC6000CWs to AC60/44CW.I think CSX did the same with it’s AC6000CWs.
UP and CSX both will upgrade them to 6000 HP units as time progresses.
The only exception is one unit that had its HDL swaped out for a 4400 HP FDL. If I remember correctly, this unit was a test bed for their super-high-tractive effort “heavyweight” or “Magnum” series of AC4400s.
The AC6000s were downrated via software for a time to 4400 HP. This was to allow GE time to work out some software bugs. Again, all the HDL 6000s are back to full power.
The 6000 HP nominal rating is nothing for that engine. I have seen the HDL (which is the basis for the new Evolution engine) run on dynometer tests well over 7000 HP for extended periods of time.
awesome, thanks for the replies. this clears things up a bit. I may have to do a trip to cajon, but i get kind of scared out there. actually, i’ll make a new thread about it.
UP’s 6000-horsepower engines are most likely all still 6000 horsepower, based on a look at information available at work. The “SD9043MACs” and “C6044ACs” were built as such, not de-rated from higher settings. I doubt that UP will de-rate them or replace their prime movers, but I understand that a bunch of the SD90s will be retired when their lease expires–shortly.
From what I know, the true SD90MACs are SD90MAC-Hs. The H is for the H series prime mover which generates the 6000 horsepower. On the Union Pacific these locomotives are all currently in the 8500 series, numbers 8500 through 8559. I’ve heard talk about these units being renumbered to the 8900 series to make room for more of the SD70ACes. As for the true Union Pacific AC6000CWs, these units are all numbered in the 7500 series. You’ll find that numbers 7555 through 7579 are all painted with the wings on the noses and the lightning bolt stripes. I have seen and heard true AC6000CWs but I don’t think I’ve seen a SD90MAC-H. If you’d like to view pictures of these locos you can find them along with many others at http://ncespee.railfan.net/UP/uptbl.html .
Just click on the link if it works or enter it into your browser. Hope this helps you with spotting these locos.
Are you sure that CSX has uprated them all (except that one) to 6,250HP? I do not remember hearing about this-last I heard was they had downgraded them all to 4400HP.
The #699 is the only C60AC still classified as a C44-6 (That’s what the 6000s were called when they were temporarly downrated). It’s the unit with the engine swap.
Like I said, all the rest of the 6000s are back to their fire breathing 6,250 HP rating.
Well:let me touch on each in varying amounts of detail. Q1: CSX permanently converted one to 4400HP after its engine fried itself, and an FDL was put in as a permanent replacement. Meanwhile the others are running at full ratings, testing the nerves of GE and CSX techs. One, a friend of mine of long standing, has told me they should be ALCOS! And he should know,[[8]) having cut his teeth on balky C430s/ C630s/C636s. [B)] They have few problems “out of the box”, but when they have run about, say, 250,000 miles (about 9-10 months on CSX) look out. Q2: On UP anything can turn up anywhere,any time, be patient. Q3: can’t help ya there,sorry. Q4: UPand CP won’t even consider it, knowing what they know. Q5: the AC6000s are like an ALCO on steroids.I got to hear (and see) CP 4744, the only M640, with an 18 cylinder 251-WOW [:0] thought I NOBODY’S gonna top this.[^] Well, The AC6000 did it. As for the SD90-H, it was a little less “throaty”,higher pitched, and quieter. PBenham
