The handover took place at the new purpose-built depot and operations centre at Laubenbachmühle, which has been built as part of a €114m programme to modernise the line.
The three-car low-floor emus seat up to 127 passengers, 11 of them on folding seats, and have a maximum speed of 80km/h.
The Mariazell Railway uses a unique 6.5kV 25Hz overhead electrification system which means all testing must be carried out in Austria. The first trials started immediately after the ceremony. The remaining eight sets will be delivered next year and the first trains will enter service in the spring, with the entire fleet due to be commissioned by December 2013.
Four sets will have an additional car with panoramic windows and 2+1 seating added in spring 2014.
Many trains on the line are still hauled by locomotives supplied in 1909-14 when the line was first electrified.
