Railroad Trains for the Soul: Heavy GEVO's
Have you ever wondered why some of the General Electric AC traction Evolution diesel locomotives are called ES44AH instead of ES44AC? What is the main purpose of an AH unit? With a heavier weight from extra ballast, it’s a solution to maximize tractive effort particularly on railroads with steep grades. CSX and Union Pacific are the major users of those diesels.
While the H broadly stands for “heavy” with respect to the extra ballast, it is not always the case for CSX. According to its criteria, an ES44AH features 432,000 pounds of weight (heavier than an average locomotive), specialized software for tractive effort and adhesion, and GE’s steerable trucks. Therefore, the H would more accurately stand for “high tractive effort” (HTE), which is not new for CSX because it originally requested extra ballast for many of its late production AC4400CW (CW44AC) units. Even the DC traction ES44DC is ballasted for the same railroad. Since 2007, CSX has purchased every ES44AH with all the HTE features. When GE introduced the Tier 4 ET44AC for production in 2015, a “heavy” version also became available, thus leading to the name ET44AH. Ironically, none of the GE Tier 4 AH units appear to have steerable trucks for CSX, but they may probably still have the HTE software on board in addition to the extra ballast.
The GE steerable truck is an optional three-axle C truck containing a special mechanism that allows the first and third axles to self-steer on curves, reducing friction and wear of the flanges. This design can be spotted by an upside-down V shape above the center axle’s roller bearing on both sides of the truck. The steerable truck has been seen on a majority of AC4400CW locomotives as well as the AC6000CW units within the CSX roster. The Kansas City Southern and the Canadian Pacific are the other Class I railroads using that truck style for many of their GE AC diesels. Because nearly all of the CSX ES44AH units have steerable trucks, they can be spotted as ES44AC’s to avoid confusion with the nearly identical ES44DC’s, the latter of which have the standard Hi-Ad (high-adhesion) trucks.
The Union Pacific is another railroad preferring AH locomotives from GE. Adding to its original AC44 units (classified as C44AC), UP initially requested a unique software called “Controlled Tractive Effort'' (CTE) for its late production diesels and designated them as C44ACCTE. The CTE software is designed to adjust tractive effort and to prevent buckling trains while a locomotive is in helper duty. When UP started purchasing its fleet of ES44AC’s, CTE became a standard feature for these units; therefore, they are classified as C45ACCTE to be differentiated from the AC44’s. Beginning in 2013, later UP ES44’s were delivered with extra ballast and are named C45AH. Unlike CSX, Union Pacific chose the ordinary Hi-Ad trucks for its “heavy” GEVO’s and all other GE AC diesels. The C45AH name is also applied to the Tier 4 ET44AH for the same railroad.
The modern high tractive effort concept is not necessarily limited to General Electric locomotives. Both Union Pacific and CSX have also acquired Electro-Motive diesels with extra ballast. The latter railroad initially applied that feature to some of its SD70MAC fleet. While UP ordered the C45AH fleet from GE, it requested additional weight for its later SD70ACe units from EMD and called them SD70AH. When EMD joined the Tier 4 locomotive market with the SD70ACe-T4 model, UP chose to add extra ballast as its standard feature for that model, so the SD70AH type also became a generic name for the railroad’s Tier 4 SD70’s (can be unofficially identified as SD70AH-T4). CSX, on the other hand, assigns its first delivery of 10 SD70ACe-T4’s as ST70AH, which is sort of a similar naming style to the GE ET44AH on its roster.
This is a photo of a CSX ES44AH unit (No. 936) that I took at the Rochester, New York Goodman Street Yard in late July 2015. The GE ES44AH units are numbered 700-999 and 3000-3249 on the CSX roster. While most of these units were delivered with steerable trucks (shown in this photo), the last 50 of them in the 3200-series appear to feature Hi-Ad trucks instead. However, most if not all the AC GEVO’s have the railroad’s signature lightning bolt painted below the roster number. As for the GE ES44DC (later redesignated as ES40DC), CSX numbered them from the 5200- to the 5500-series. All of these have Hi-Ad trucks but lack the lightning bolt under their numbers, indicating their DC-traction configuration. I hope this explains the details behind the GE ES44AH and ET44AH as well as the EMD SD70AH and SD70AH-T4.
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