Czech Railways (ČD) operates a train from Prague to Bad Schandau every 2 hours. Tickets cost $13 - $19 and the journey takes 1 h 45 min. Alternatively, FlixBus operates a bus from Prague to Bad Schandau hourly. Tickets cost $8 - $14 and the journey takes 1 h 55 min. 4 other operators also service this route.
From Praha hl.n. train to Bad Schandau. 1 h 45 min 339 Kč. From Prague, Prague ÚAN Florenc bus to Dresden Hbf then train to Bad Schandau. 3 h 24 min 646 Kč. From Prague drive to Bad Schandau. 1 h 35 min 446 Kč.
Yes, there is a direct train departing from Praha hl.n. and arriving at Bad Schandau. Services depart every 2 hours, and operate every day. The journey takes approximately 1¾ hours.