CSX SD70MACe improvements

[David Collins]

Just out of curiosity, Does anyone know what improvements were made to the CSX SD70MAC when they were rebuilt to SD70MACe specifications? Details are extremely hard to come by.

[SD80MAC]

“SD70MACe” is a BNSF designation which is not used by CSX. CSX classifies their rebuilds as “SD70AC”, same as their SD70MACs. The units received had their old Siemens electrical systems replaced with new ones from Mistsubishi (?). I believe they also now have individual axle control inverters instead of the original set up of 1 inverter per truck. I believe the steering linkage for the HTCR trucks was left intact. The units received cab refurbishments but did not receive all new cab interiors like the GE rebuilds, retaining their original desk top controls. Some of the newer ones have been confirmed to have DPU equipment, but this has only happened recently.

[Saturnalia]

“SD70MACe” is a BNSF designation which is not used by CSX. CSX classifies their rebuilds as “SD70AC”, same as their SD70MACs. The units received had their old Mitsubishi (?) electrical systems replaced with new ones from Siemens. I believe they also now have individual axle control inverters instead of the original set up of 1 inverter per truck. I believe the steering linkage for the HTCR trucks was left intact. The units received cab refurbishments but did not receive all new cab interiors like the GE rebuilds, retaining their original desk top controls. Some of the newer ones have been confirmed to have DPU equipment, but this has only happened recently.

Echoing what SD80MAC said, most of the updates are internal to the electronics and computers, so visually not much has happened, aside from all units being repainted, with the Huntington Rebuild sticker on them. These are much closer to a refurbishment than a rebuild, if you will.

I'd bet that if Tier 4 wasn't a thing these SD70ACs would be sitting dead or already retired and new SD70ACe or ES44AHs would be on property. Alas the additional cost to purchase, maintain and fuel a Tier 4 locomotive means that rebuilding these older units is more economical that it otherwise would have been, for better or worse.

To some degree it's sort of a backfire on the regulation intended to improve emissions, as it has led to essentially all of the Class Ones investing much more in rebuilds of older Tier 1 or older locomotives, than buying new Tier 3 or 4. Whoops.