BOSTON — A complete upgrade of the Massachusetts Bay Transportation Authority’s commuter rail system could cost up to $33 billion, according to a study presented at Monday’s MBTA Fiscal and Management Control Board meeting.

Bisnow.com reports that the presentation outlined three options:

— For an estimated $33 billion (in 2030 dollars), full electrification of the MBTA system, expansion of South Station, and construction of the Grand Junction shuttle between Cambridge and Allston.

— For $7.5 billion, electrification only of the route to Providence, expanding service on the Foxboro line, and operating diesel trains on other lines on 15-minute headways.

— For $3.1 billion, expansion of the South Coast Rail project. [See “Groundbreaking marks start of work on MBTA’s South Coast extension,” Trains News Wire, July 3, 2019.]

The costliest option would include replacement of the entire MBTA equipment fleet. It is also the only one to include South Station expansion, although that is expected to be needed under any improvement plan.