Note: Info presented here only pertains to Block ID codes found on sites like Pantograph or Catenary Maps. Internally, a different system is used(Run #s).
IDs will show up in the following formats (Z is a letter placeholder, # is a number placeholder)
Z##-### (For 1 or 2 Digit routes)
Z###-### (For 3 Digit Routes, including SL and CT routes)
The letter Z indicates which garage the bus operates out off.
The first set of #s (Between Z and -) indicates the Route number.
The second set of #s (after the -) indicates the block number for that garage.
A-Albany Garage (Cabot division weekdays day only)
B-Arborway Garage
C-Cabot Garage
F-Fellsway Garage (Charlestown district weekdays day only)
G-Charlestown Garage- Charlestown District
L-Lynn Garage
Q=Quincy Garage
S-Southampton Garage (60' busses for Silver line, 28, and 39)
T-Charlestown - Bennett/Somerville District
708 - CT3
741 - SL1
742 - SL2
743 - SL3
746 - SLW
747 - CT2
749 - SL5
751 - SL4
rad - Run as Directed (Extra Runs)