IAD Mobile Lounges at JFK?

[WMATAGMOAGH]

No photos, sorry, but I saw what looked to be 3 or 4 former IAD mobile lounges from a taxiing Delta Connection plane en route from Boston to Kennedy on Tuesday morning.  Does anyone know exactly what happened to these units once Aerotrain opened?  I know some are still in use for Terminal D and international arrivals but I believe many were decommissioned.