Im not used to seeing CSX units out here, so today when a ES44AH rolled through on a manifest, i wondered, what is the difference between a ES44AH and ES44AC?
I read in a different forum (can't vouch for the source) that the "H" means they have the "High Tractive Effort" software. That differentiates them from the plain old AC units.
I believe that indicates that the units have concrete weights in them so they're heavier than a standard ES44AC.
You guys are both right. The "H" stands for Heavy w/ High Adhesion software. CSX has been adding extra weight to their AC units for about the last 10 years or so now. I'm not a big CSX fan, so I can't tell you numbers and all the specifics, but I think it started on the (CSX only) SD70MAC's and AC4400's. I Know for sure on the SD70MAC's CSX added a 1,000+lbs to the units. Some of that weight in the form of thick steel sheets can be seen on the walkway behind the cab on the engineers side of the MAC's it's the slightly raised portion (a little modeling detail). I'm not sure what they did on the GE's? As far as the use of concrete I'm not sure, it's a vulnerable material in a freight unit, I know Amtrak used it in the cabbage cars. More than likely the weight is built into the unit somewhere ie: beefier frame, steel plates here and there.
IIRC, Milwaukee Road's Little Joe electrics had concrete poured in pans in the locomotive to increase TE. They added around 80,000# of ballast to these units. BoxcabE50, can you confirm?
The high adhesion program allows the locomotive to generate much higher tractive effort at speeds below 10 MPH. These locomotives are also equipped with a "rail cleaner" which blows air across the railhead to clear leaves, snow and moisture to help the locomotive maintain pulling power.
On a mountainous territory a CW44AC unit is rated for 3650 tons and a CW44AH is rated for 3950 tons. On a flatland territory a CW44AC is rated for 18350 tons and the CW44AH is rated for 19950 tons. In comparison the SD70MAC are rated for 3450 and 17300 on the two territories
