As of August 2017, there are still no passenger train services from Antananarivo. (For a while, the vintage Micheline did run a tourist trip from Antananarivo at weekends, but it no longer operates any services.) Passenger trains in Madagascar run on at least one day per week on the following routes:
Moramanga to Toamasina (Tamatave)
Moramanga to Ambatondrazaka
Fianarantsoa to Manakara
Each of these journies takes between half a day and one day.
At madarail.mg you can find an overview of current routes.
Antananarivo and Antsirabe are not on it (September 2014).
No, there is only cargo rail service between from Antananarivo to Antsirabe.
The only public transportation options are taxi-brousse and plane.
Credit:stackoverflow.com‘