Cem,
As it happens Roco are bringing out a set of Epoch I Bavarian
Lokalbahnwagen this year, item no 46000:

These could easily be supplemented by further long (
Lange) coaches from ebay as follows:
Roco set 44018 - 2 x CL, 1 x BPostL and 1 x Pwl
Roco 44827 - CL
Trix 23019 - BCL
Trix 23020 - CL
There is also the Ludwig Thoma branch line set which includes a classic D XI loco plus BCL, CL and PPostL - Trix Set 21226
Finally Roco do a set of 4 'short' (
Kurze) coaches (no 44014) if you prefer also obtainable on ebay.
If you're only modelling one station, you can probably get away with 2 locos (e.g. a D XI and a GtL 4/4) plus 2-3 CL, 2 GwL and a few goods wagons
(say 3 x O and a couple of specials). For variety, make a handful of loads for the open wagons.
HTH