TFC: Transferoviar Calatori (passengers) private open access operator on the Romanian Railways Network.
TFC operates connections on the following routes:

Bucuresti Nord - Buzau
Cluj Napoca - Oradea
Galati - Barlad
Titan Sud h.m. - Oltenita
Buzau - Nehoiasu
Ploiesti Sud - Slanic
Bucuresti Nord - Galati
Ploiesti Sud - Maneciu
Târgovişte - Pietroşiţa
Ploieşti Sud - Târgovişte
București Nord - Târgoviște
Costești - Roșiori

This app is the official one and it offers access to all the available information: looking up routes by station names or train numbers the possibility to view and save timetables for viewing at any time (even without Internet for the offline ones).

Offline files are saved as PDF therefore you will need a viewer app for this file format in order to use the offline favorites functionality.