ES44C4 Mechanics

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ES44C4 Mechanics

  • I am looking for information on the workings of the traction control of the ES44C4. The mechics of the system rather than electronic. From the looks of the picturers that I have seen it looks very basic, somehow the air cylinders via linkage piviot a device to unload the axle. How does this work? It also seems to me that just shuting off power to a traction motor on a given axle to save fuel would cause quite a bit of drag.  Reverse gear reduction turning a large unpowered motor. It makes me wonder why, if tractive effort is best with four axles on heavy rail, then why have six in the first place? With a tractor-trailer if the axles are not needed for weight distribition they are raised of the road. Is this the same concept?

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  • aut1rml

    I am looking for information on the workings of the traction control of the ES44C4. The mechics of the system rather than electronic. From the looks of the picturers that I have seen it looks very basic, somehow the air cylinders via linkage piviot a device to unload the axle. How does this work? It also seems to me that just shuting off power to a traction motor on a given axle to save fuel would cause quite a bit of drag.  Reverse gear reduction turning a large unpowered motor. It makes me wonder why, if tractive effort is best with four axles on heavy rail, then why have six in the first place? With a tractor-trailer if the axles are not needed for weight distribition they are raised of the road. Is this the same concept?

     

    There are only four traction motors on a C4. The four traction motors are capable of providing more pulling power than the wheelslip (traction control) can utilize when the locomotives weight is evenly distributed on all six axles. What GE's system does is take some of the weight off the center axle of each truck and transfers it to the outer axles. With more weight on the outer (powered) axles more torque can be produced without spinning the wheels. You might ask why not build a 4 axle locomotive instead, the answer is that the total weight of the locomotive would be too high, even though some of the weight is transferred off the center axles, contrary to early rumors, the axle isn't lifted off the rails.

  • I'll just add that the ES44C4 is really a poor-man's 4 axle AC locomotive - which is the equivalent of a six axle DC locomotive. Trying to get all the components and fuel capacity onto four axles without very high axle loads is not simple, nor cheap... Taking two motors out of an existing 6 axle design is cheap and easy....and quick to market. The difference between the ES44C4 and an ES44C occurs between roughly 8 and 12 mph. If BNSF is using them on trains that are powered such that they don't ever drop below 12 mph on the ruling grade (which is what they are now doing with their six axle DC fleet), the extra two motors are merely dead weight, so why carry them around. The unloading mechanism is for those rare occasions when the train's a little heavier than they figured or one of the other locomotives in the consist is a bit sick. It give a little extra oomph - which may be the difference between getting over the hill or not. It's cheap insurance. If these cost roughly the same as a six axle DC unit, then BNSF saves maintenance money as AC propulsion is cheaper and more reliable than DC.

    -Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

  • I wouldn't be surprised if the lifting center axle turns out to be a short lived idea.  Surely the added complexity in the truck will result in additional maintenance, a nuisance at best, and it could prove more costly than the savings from fewer traction motors.  The ES44C4 concept could instead continue using a more standard truck.  Just my thoughts - it will be interesting to see how they work out in the longer term.

    John

  • I have seen then in service.  All GE did was add one extra Air Brake Cylinder and one Bellcrank and 2 rods to reach the crank and axle per side of the truck.  What happens is when the computer thinks the engine needs the Tractive Effort it applies air to the Cylinder and via the bell crank it pushes up on the axles compressing the suspension for that middle axle.  It transfers 25% of the weight of the axle to the other 2 in the truck and boosts the TE of the unit til about 15 MPH then releases the air and lowers the axle.  There is no control in the cab and if there is a fault it will not work.  BNSF is reporting the same power aviablity as the standard GEVO. 

    Always at war with those that think OTR trucking is EASY.
  • edbenton

    It transfers 25% of the weight of the axle to the other 2 in the truck ...

    I have looked for information on how much weight is transfered but have been unsuccessful until I saw this.  Is this an official number from GE or someones' estimate?

    Dave

  • From talking to a couple of people I have at the BNSF in the Mechnical Department.  That is what GE's Engineers thinks it transfers plus that would be about the max for Axle loading on the engine based on the Published Weight and max Axle loadings allowed.

    Always at war with those that think OTR trucking is EASY.
  • oltmannd
    I'll just add that the ES44C4 is really a poor-man's 4 axle AC locomotive - which is the equivalent of a six axle DC locomotive. Trying to get all the components and fuel capacity onto four axles without very high axle loads is not simple, nor cheap... Taking two motors out of an existing 6 axle design is cheap and easy....and quick to market. The difference between the ES44C4 and an ES44C occurs between roughly 8 and 12 mph. If BNSF is using them on trains that are powered such that they don't ever drop below 12 mph on the ruling grade (which is what they are now doing with their six axle DC fleet), the extra two motors are merely dead weight, so why carry them around. The unloading mechanism is for those rare occasions when the train's a little heavier than they figured or one of the other locomotives in the consist is a bit sick. It give a little extra oomph - which may be the difference between getting over the hill or not. It's cheap insurance. If these cost roughly the same as a six axle DC unit, then BNSF saves maintenance money as AC propulsion is cheaper and more reliable than DC.

     

    I believe you are correct about the new units being a poor man's 4 axle locomotive that is equal to a DC model with six motors.   These units were purchased to be used on stack trains that require more HP at higher speeds.  Having four axles with 4400 HP allows up to 1100 HP for each axle which does not lend itself to drag service even with the extra weight that can be transferred up to 12mph or so. 

    Three of these on a stack train on the transcon could conceivably replace four of the regular 4400 HP six axle units since high speed is the name of the game.  Remember the reason the UP wanted the 6000HP six axle models, it was to use on high speed trains where the HP makes the difference.  

    They have been spotted on every type of service so far, but the real use might be to replace the 8-40BW units which had 4000 HP for four axles.  These units were used on the stack trains for many years. 

    CZ

  • CAZEPHYR
    Remember the reason the UP wanted the 6000HP six axle models, it was to use on high speed trains where the HP makes the difference.  
    When UP et. al. were considering 6000 HP AC units, the goal was a universal replacement for 4000 HP DC units. HP for HP and #TE for #TE, they'd replace the the DC units 2 for 3. Two 6000 HP AC units would be able to take most any train currently operated.

    -Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/

  • I wonder what the relative cost of two 6000 hp locomotives are compared to three ES44C4's?
    Revision 1: Adds this new piece Revision 2: Improves it Revision 3: Makes it just right Revision 4: Removes it.
  • CAZEPHYR
    Three of these on a stack train on the transcon could conceivably replace four of the regular 4400 HP six axle units

    The A1A-A1As could conceivably pull 33% harder than a DC C-C? Why would they?

  • timz

    CAZEPHYR
    Three of these on a stack train on the transcon could conceivably replace four of the regular 4400 HP six axle units

    The A1A-A1As could conceivably pull 33% harder than a DC C-C? Why would they?

    The way I understand the deal is, the higher HP per axle equals higher HP at speed for stack trains.  The A1A would not lug better than a C truck unit, but would have better higher speed pull.  More HP per axle is needed for trains at higher speeds, but is a disavantage on a heavy train at slow speeds.   I have not heard or seen any more orders except for the 25 units.  Does anyone know if the C4 units are working out OK?? 

     As far as using three instead of the four units, this is an example of AC versus DC power and the fact the AC will lug better than a DC model.  I do not know if the testing has been sucessful or not.  GE had a commercial about the new AC model and the fact it had a twenty some percent fuel savings over the DC model.  I had not heard that sales pitch until the commercial.   It would seem the big advantage for the new units is the AC motors and fuel savings.  In practice, I doubt three will replace four units since they are all the same horse power just distributed over a different amount of axles.  

    The old 8-40BW models used to be used on stack trains the first ten years of their service life, but usually had five units on the train.    The 500 series 8-40BW were DC models rated at 4000 hp like the 8-40CW's at that time.  

     

    CZ

  • From the Scanner chatter I hear helps being 2 blocks from the Transcon the Crews LOVE THEM.  However they were part of the GEVO turbo issue and were down while those were replaced.  Now they are coming back online and are being used bigtime.  Just yesterday saw the big 10K footer that they run come thru with 4 on it 2 on the head end and 2 pushing.  Since right now Streator is a slow zone due to track work the BNSF was replacing both the NS Diamond and the RT 18 crossing they were only giving the trains 15 MPH til they hit 12th St on the south end of town.  Lets just say I got to see them pull out and I could have sworn I was watching a set of SD-40-2 pulling this thing the way they accelarated.  When they left the restriction they were at 15 when they hit the Next detector they were at 50 in 2 miles.

    Always at war with those that think OTR trucking is EASY.
  • Well, most male dogs (not counting silly poodles or stupid Chiahuahuas) lift an axle when they want to better distrubute their body weight.  The jury, methinks, is still out on the ES44C4s.  One came thru here the other day, but I didn't pick up the 6600 number on the scanner in time, ergo no photo.  6609 was leading a mixed lash-up with Dash 9-44CWs.  I figured most of them would be down on the "Transcon", but they are up here, on the "Hi-Line", too.  Also, there are two  pistons, on each side of the truck to lift the idler axle.

    Hays -- Shelby, MT 

  • oltmannd
    The unloading mechanism is for those rare occasions when the train's a little heavier than they figured or one of the other locomotives in the consist is a bit sick. It give a little extra oomph - which may be the difference between getting over the hill or not. 

    Another ES44C4 feature that may help in this kind of situation is the ability of each of its traction motors to produce a maximum of 36,000 pounds of tractive effort, rail conditions permitting, as opposed to the 30,000-pound maximum that each motor on a standard ES44AC can produce.