Here’s the first closeup of the A-1-A ES44AC4 I’ve seen. BNSF 6615 at Hesperia, CA.
http://www.locophotos.com/PhotoDetails.php?PhotoID=101123
A very beautiful and expensive, AND computeride machine. Would that happen to be a SD70M that it is leading? Just remember this unit will look as dirty as some of the -9 do now in a few years! Good catch and shot though!
The road to to success is always under construction. _____________________________________________________________________________ When the going gets tough, the tough use duct tape.
Lyon_Wonder Here’s the first closeup of the A-1-A ES44AC4 I’ve seen. BNSF 6615 at Hesperia, CA. http://www.locophotos.com/PhotoDetails.php?PhotoID=101123
The weight transfer system on the center (unmotored) axle is a clever concept. It lifts the frame up transferring weight to the 2 powered axles when additional tractive effort is needed...
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
she's a real beauty
I thought it was somethibg of that class. One of my favorite engiens.
I am seeing them quite a bit on the Transcon anymore. From what I can tell the crews like them from the Scanner chatter.
Where is BNSF using these units? I hang out at Fullerton quite a lot and I haven't seen one yet.
There are 25 total on the roster not sure if they have all been delivered Numbered 6600-6624 Plus they are running System wide so they are all over the place also. Do the math 29K trackage miles and only 25 units so less that one per 1000 miles of trackage that the BNSF runs on.
I like the newer GEs, they have a balanced look to them.
I notice the newest ES44AC/DCs have their nose-door on the right side. Most GE widecabs, from C40-8Ws to the ES44AC/DC, had the nose door on the left side. I've even seen a pic of a newer BNSF GE using a nose door from an ex-Conrail C40-8W. EMD made this change from left-side to right-side nose-door placement in the mid 1990s.
What is this 'weight transfer' system? I was not aware of anything special there, just the lack of traction motors/inverters for the middle axles. Transfering weight will not create additional TE, and will take the engine over the maximum axle loading.
Jim
Modeling BNSF and Milwaukee Road in SW Wisconsin
jrbernier The weight transfer system on the center (unmotored) axle is a clever concept. It lifts the frame up transferring weight to the 2 powered axles when additional tractive effort is needed... What is this 'weight transfer' system? I was not aware of anything special there, just the lack of traction motors/inverters for the middle axles. Transfering weight will not create additional TE, and will take the engine over the maximum axle loading. Jim
Read the caption on this photo:
http://www.railpictures.net/viewphoto.php?id=276628&nseq=12
Supposedly this is called a "dynamic weight management" system" and kicks in below 15 MPH...You can see the hydraulic cylinders in the photo. As far as exceeding maximum axle loadings obviously it doesn't completely unload the center axle.....
carnej1 Read the caption on this photo: http://www.railpictures.net/viewphoto.php?id=276628&nseq=12 Supposedly this is called a "dynamic weight management" system" and kicks in below 15 MPH...You can see the hydraulic cylinders in the photo. As far as exceeding maximum axle loadings obviously it doesn't completely unload the center axle.....
They look an awful lot like air brake cylinders (compare with the other air brake cylinders) so I'd guess the system is pneumatic and not hydraulic - you have plenty of air to do this with. A similar pneumatic system unloaded the leading and trailing trucks of Chinese QJ class steam locomotives, although I'm not sure that it is fitted to the units that came to the USA.
If the ES44AC4 units are not ballasted up to full axle load, there might be some transfer allowable. If the transfer only occurs when starting on plain track some increase might be allowable over normal maximum loads.
M636C
I agree thay do look a lot like air cylenders. Wouldn't that like snapp the 2 axels on the truck that were powered? What is the weight limit? Like Jim said, wouldn't that over load the axels? It sounds ingenious though. Too the middel of the truck would have to be able to flex or pivot. Also Jim, It would concentrate the pulling power though right? Be nice to hav that on a steep grade!
From what I can see what this look like is something simalar to what in the OTR industry we would have called a DUMP VALVE for our air ride suspensions for getting out from a trailer. Basically what happens here from what I can tell is the cylinders can slightly pick up the center axle tranfering the weight to the outer 2 axles without totally removing it from the rail. It may onlly give each of the others an extra 20K at a time however it would equate to an 10K in tractive effort maybe so well worth the effort of keeping the system functional.
I spotted my first ones yesterday, and got a few photos that can be seen here.
Visit look4trains.com
Your have to be right, I've never seen anything hydraulic on a locomotive. I know the Chinese JS engine that is on the Boone and Scenic Valley in IA still has the weight transfer system in place; however the air supply lines have been removed. I'm sure when it works right it's and amazing system like most GE's. I've seen them work good twice now!
Hey guys,
I can't help but wonder if it wouldn't be cheaper and more practical for BNSF to simply convert some of the older but still servicable B40-8s or GP-60Ms from DC to full AC traction status...
If this is possible, a "B40-8AC" or "GP-60MAC" could probably perform just as well in similar applications as the ES44AC4 but just might be more cost effective.
Whaddaya think?
Randy
rhermen Hey guys, I can't help but wonder if it wouldn't be cheaper and more practical for BNSF to simply convert some of the older but still servicable B40-8s or GP-60Ms from DC to full AC traction status... If this is possible, a "B40-8AC" or "GP-60MAC" could probably perform just as well in similar applications as the ES44AC4 but just might be more cost effective. Whaddaya think? Randy
There really is no way to "simply" convert a DC traction unit to AC traction..
Firstly, the AC propulsion system (including inverters, traction motors and other equipment) is expensive, so much so that the few locomotives I know of that were remanufactured to AC drive from DC (Ex New Haven RR FL9's) cost almost as much to rebuild as buying brand new locomotives would have. This is also a major reason why the big Class 1 RR's have not rebuilt older 6 axle power like SD60s etc. into AC units...
In addition, the units you mention are about as heavy as a BB freight unit can get and there really is no room on the frame for the inverters, etc. In fact the B40-8 widecabs that ATSF bought had to be delivered with smaller fuel tanks to meet the weight limits for four axle units.
The same issues above would apply to new production "GP70Ace" or "ES44AC-B" locomotives..
There was a longer technical discussion about this on an earlier thread, which you can read if you type "A1A BNSF" into the SEARCH COMMUNITY box on the right side of this page..
I bet EMD has their own version ready to come out.
fecsd40-2 I bet EMD has their own version ready to come out.
While that certainly is something that EMD may be doing design work on there are a couple of reasons it may be more difficult for them. Firstly, since EMD was spun off from General Motors they have much less available money for R&D and Product Development than they used to (and esp. when compared to GE). Also one of the economic advantages of the GE units is that they use 4 rather than 6(as in a "conventional' ES44AC) AC inverters. GE's AC traction system uses one inverter per axle so t 2 fewer traction motors equls 2 fewer inverters. EMD 6 motor AC locomotives have only 2 inverters, one for each truck, so a four motored version of the SD70ACe will still have to have 2, so the price of the locomotive may be closer to that of a 6 motor unit..
Our community is FREE to join. To participate you must either login or register for an account.