by Mr. Know It All
The SD60MAC's are oddballs. the traction motor pinions and corresponding bull gears, inverters, and control system is totally unique to these "prototypes". Siemens no longer supports them and parts are impossible to find. They are tired units to start with after getting their pants run off all over the country. They have never been overhauled. they have governors, not EMDEC so they are not "up to date" on emission and not suitable for new engine component testing. In short....they are worn out and obsolete. For years they have been used as little more than "boat anchors" at TTC to simulate heavy tonnage for testing on other units like the SD70Ace. The units will almost certainly return to TTC and become prototype test beds. As long as they remain at TTC, they are basically "exempt" from FRA requirements as that is what TTC is for....development.