To get to Larissa Railroad Station for trains to Evia and Northern Greece you can take the trolley bus no.1 from Venizelou (Panepistimiou) Street. You can also take the Metro Line 2 "Syntagma to Sepolia and get off at the train station stop. The Peloponnese Station is right behind the Larissa Station.
These schedules are a little old but they will give you an idea of frequency and in many cases have probably not changed. When in Greece you can get train information by dailing 1440. (Recorded)
The OSE Main Information Centre is at 13, Karolou Str. Athens. Tel: 30 210 5297777
Special information and facilities for disabled persons:
+30 210 5298838 for Athens
+30 2410 590263 for Larissa
There are OSE employees in charge at all stations in Athens and Larissa, that facilitate transportation of disabled persons.
This schedule was posted on June 13 2010 though there were few changes from the previous schedule that was from 2008. (Besides the National Train Company going bankrupt)
No offence to OSE but if you have 4 or more people in your party take a taxi
Athens Practical Info Index