Perm stix instead of perm marking/cardboard writing.
BBDEP rarely use perm stix, so it's AMDEP. Plus it cameoed on
166 before IIRC.
BB sometimes use perm stix. Rode 9612B. It has sv74 on it.
3190R cameoed on sv147 and lately sv151. Both belonging to
BB.
I dont think BB would give a cross depot transfer to AM. BB is
west and AM is east.
Take a look at the bus driver who drives the bus is also another
way to tell which depot he belongs to.
However, a bus driver from BB can go to AMDEP to have
mealbreaks. Vica-versa. 3017J once came back from AMDEP to Amk int
with off service.