21. Nov. 1896 Director Ing. Josef Fogowiz startet to built the narrow gauge railway from St. Pölten Hbf to Kirchberg/Pielach.
7. June 1898 First test-train arrived in Kirchberg. The railway is operated by the NÖLB (Lower Austria Local Railways).
2. July 1898 Opening of the part from St. Pölten to Kirchberg (31.3 km)

As locomotive the NÖLB used the common class U ("U" for Unzmarkt/Murtal-railway) wich was built at Krauss/Linz. (Travel speed 25 km/h

Dampfzug im Bahnhof Frankenfels, um 1900
since 1903 Because of the many passengers at short trains, the NÖLB used additional steam-multiple-units. (Increase of the travel speed to 30 km/h)
1904 The track from Kirchberg to Laubenbachmühle was started to built.
5. Aug. 1905 Opening of this railway-part (Lenght about 50 km).
March 1905 The NÖLB started to built the mountain-part from Laubenbachmühle to Gusswerk (Styria).
17. Dec. 1906 The first freight train should arrive in Mariazell. Because of the bad weather it only reached Winterbach.
19. Dec 1906 The first train really arrived in Mariazell
15. July 1907 The offiziall opening of the whole railway from St. Pölten to Gusswerk.
1906 The NÖLB orderd new steam locomoitives of the class Mh ("M" for Mariazell, "h" for Heißdampf/hot steam). The number 6 of these is today lovely restaurated and is still in use for nostalgic trains.
7. Oct. 1911 Beginn of the electric operation between St. Pölten and Gusswerk..

For the electric operation, the NÖLB ordered 16 new electric locomotives (class 1099). They are one of the first single phase alternating current locomotives. For the electric power a water power station in Wienerbruck was built.

1099 bei Kirchberg
1923 A second water power station in Erlaufboden was built.
15. July 1922 The Austrian Federal Railway (ÖBB) operate the Mariazell-Railway.
in the late 1950s Rebuilt of class 1099 to the actual form.
29. Sept. 1988 Stopping the operate between Mariazell and Gusswerk and of the freight service between Loich and Mariazell.
1995 New electric-multiple-units of the clas 4090/7090/6090 started to operate on the railway.
31. Dec. 1988 Stopping of the freight service on the whole line.
Mai 1995 For the people's transport on the Talstrecke between St. Pölten and Laubenbachmühle the ÖBB used disel-coaches of the class 5090 without toilettes.
7. Oct 2001 90-Year jubilation of the electric service
12. Dec 2010 The NÖVOG (Lower Austria Transport Organisation Company) take some local railways in Lower Austria. Also the Mariazell-Railway.
3. Dec. 2011 The NÖVOG startet to built a new service center in Laubenbachmühle.
27. Oct. 2013 Modern low floor multiple-units are on service at the Mariazell-line.

The old class 1099.14 had the honor to bring the last "old" train from Mariazell to St. Pölten

1099 bei Schwarzenbach
June 2014 A new electric power station in Klangen started to operate.
Summer 2015 The Mariazell-Railway with it's service center is one big point of the Lower Austria exhibiton "ötscher:reich"