Minor note: During Green Line D branch shutdowns, shuttle buses typically use Beacon St, Park Dr and Brookline Ave, so that they can stop right at Fenway station on Park Dr.
As for Alewife, I wonder if it's better to run shuttle buses from Porter instead of Davis. However, that will be confusing operationally.
Got it, tweaked the map slightly.
So a Brookline Village - Kenmore /Lansdowne Station rail replacement shuttle bus route is slightly longer, with a deviation to Beacon St. to serve Fenway Station, instead of remaining on Brookline Ave. directly to Kenmore. It is faster for a passenger to board a Route 60 bus to Kenmore, instead of taking a Highland Branch rail replacement bus; that boards at Rt 60's bus stop at Longwood & Brookline Ave.; that subsitutes the D's Longwood stop.
It goes to show how running rail replacement shuttle buses is very difficult to do for railway ROW routes that do not follow street grid patterns. The more direct street routing you choose, the more further distance the front door to a subway and railway station is from the rail replacement shuttle bus stop. Given rail replacement shuttle buses need high frequency to mimic subway frequencies and capacities, an indirect routing on the street grid is a huge penalty for maintaining frequency. The most direct street route is usually served by a more direct and ordinary bus route. It's a problem when running buses overnight as a night bus network, how do we deal with the subway and rail routes with no bus route?
Only the outer portions of the B, C, and E branches are busable immediately. The E branch is subsituted with the 39 bus. The B and C branches just need equivalent bus stops, outside of the 57 on Commonwealth Ave. The shuttle buses for these 2 branches follow the most direct route, so there is minimal delay, and a rail replacement bus can operate to and from Kenmore Station to Cleveland Circle and Boston College in a reasonable time and speed. They can also be given a bus route no# for their surface portions west of Kenmore, say, 56 and 53 for the B and C. The western portions of the B and the C Branches are the hidden portions of the bus network, having been the only 2 routes to not be axed from the historical streetcar network, and therefore displayed on subway maps and omitted from bus maps.
This might go into the Crazy Transit Pitches/Infrastructure sandbox thread, but if a hypothectical Highland Branch operated as a rapid transit subway line into South Station via I-90, rail replacement shuttle buses would need to serve Lansdowne Station, instead of Kenmore Station. 2 crazy ideas: can rail replacement shuttle buses could remain on Beacon St. and stop there? Or if is it better to stay on Brookline Ave., and have Fenway passengers board shuttle buses a bit ways away from the subway stop? It's an interesting idea, if we convert another rail ROW into a subway line, then that's another route that needs rail replacement shuttle bus routing onto the street grid.