Sometimes it seems there are way more trains running in the counter-peak direction than the peak… particularly towards the end of the morning peak, and before the evening peak.
This is because there’s little train stabling in the central city area, so most trains have to be sent back to the burbs between the peaks. There used to be heaps of stabling between Flinders Street and Richmond for instance, much of which has been taken over by the tennis centre and housing around Jolimont.
Many of these trains (at least in the morning) run in service, so for instance at around the time I’m heading into the city, the scheduled counter-peak trains at Bentleigh (8:11, 8:15, 8:20, 8:27, 8:30) are way more frequent than the peak (8:06, 8:15, 8:29).
Some of those counter-peak morning trains terminate at Moorabbin and run back into the city, thus taking at least two AM peak loads each morning.
In contrast, many buses along the Centre Road 703 route seem to run out of service between Brighton and the South Oakleigh depot. This is a shame, but I suppose too many passengers would impact running times and blow out costs/break times — probably inevitable while bus drivers are selling tickets.