Two train sets were completed at the Motivepower plant at Mountain Top, Pennsylvania and were tested. The project was dropped when CSX got involved in the Conrail acquisition, the people who worked on it were all let go, and the two train sets with their adapter cars were transferred to CP Rail and were tested in service there (I believe Montreal to Toronto). I have not heard anything about them in many years and considering their unusual one of a kind systems and the need for captive locomotives that were specially fitted to adapt to them, I doubt they are still in use.
If you are thinking about writing anything about them be aware that the CSX lawyers generally contact anybody who offers any information about them (particularly on eBay) and threaten legal action to protect their intellectual property rights. This is despite the fact that they abandoned the project a decade ago.
"We Repair No Locomotive Before Its Time"