This is from several months back, but an E233 set (2000 sub series Mato 10) used on Joban Line local service was sent to Nagano General Rolling Stock Center to be fitted with CBTC equipment. After a stay of almost three weeks*, it returned to its depot at Matsudo, pulled by an EF64 based out of the Nagaoka Rolling Stock Center. Locations are Hachioji and Kunitachi.
*apparently fitting of CBTC equipment is quite involved/complicated, it required about 10 days per trainset for London Underground Northern Line stock to be fitted with like equipment.