Thats 1 strong repeater, blowing my doors off.
It's not just one repeater, since Areawide 4 is used over all of eastern MA. The BAPERN system has been in place since the mid 1970s and has expanded and improved over the years. Interop got an early start in eastern MA due to civil unrest at Harvard University in 1970. The various agencies used different bands and frequencies and there was no common frequency available to officers in the field. The existing VHF Intercity frequency was only for use base to base.
The BAPERN system was conceived and built using the then newly available UHF-T band. As technology progressed and radios became more broad banded, regular UHF frequencies were added to the mix. That allowed Quincy and some other departments to have radios that operated on the BAPERN regional and system wide frequencies and retain their UHF channels for local operations.
About 1980 or so, Metrofire which covers the greater Boston area, started a similar migration to the 48x. part of the T band.
Both systems got a lot of federal funding after 9/11 and BAPERN in particular expanded to cover a much larger area than initially planned.
Massachusetts, particularly eastern MA, is very well set up for interoperability. We saw that in use during the past several days as police officers from all over the state as well as New Hampshire and even NY City were able to communicate effectively.
I think it worked pretty well myself.