Yes, you are quite right about Brighton Beach. However, I am not aware
of suburban trains stabling there in recent time. Unfortunately, I rare
use the Sandringham line, thus someone else probably can answer this
question better than I can.
Finally, I just like to point out that to reduce vandalism overnight,
the Met Train have stable trains in various places around Melbourne.
These locations have high fences, barbed wires, lighting and security
cameras. Places like Brighton Beach, Camberwell, Victoria Park, etc.
would not be used for stabling trains overnight. However, they may be
used to stable trains for short time only.
I.C.