in use. The section from Ober-Grafendorf to Mank was the last part of the line to see narrow gauge trains, but has not been used since 2010. There are plans to convert this latter section into a heritage railway. Operation On weekdays, Himmelstreppe trains operate every hour between St. Pölten and Laubenbachmühle. Depending on the time of year, between 6 and 10 of these trains continue to and from Mariazell. On weekends and public holidays, a slightly reduced service is operated, but this is supplemented in summer by some regular trains hauling panoramic coaches, and by additional trains hauled by electric or steam locomotives. Accidents and incidents On 26 June 2018, a Himmelstreppe unit was derailed at St. Pölten. Thirty people were injured, three seriously. Rolling Stock The normal passenger service on the line is now provided by a fleet of nine low-floor EMUs built by Stadler Rail, which entered service between 2012 and 2014. In summer these pull matching panoramic first-class coaches from a fleet of four. The three-car articulated EMUs are designed to operate up to 80 km/h, and are prominently branded Himmelstreppe ("Stairway to Heaven"), a name chosen to reflect the line's terminus in the pilgrimage centre of Mariazell. A number of the line's older electric locomotives (the 100-year-old class 1099), diesel locomotives (class 2095), diesel railcars (class 5090) and passenger coaches have been retained for special services. Additionally, one class 1099 has been donated to the Vienna Technical Museum and another may be rebuilt to return it to its original, pre-1959, state. The two class 4090 EMUs, built in 1994, are stored out of doors at St. Pölten Alpenbahnhof and face an uncertain future. The remaining stock has all been stored, sold on or scrapped. For nostalgic runs, the Mh.6 steam engine stationed in Ober-Grafendorf is brought in. This was a private initiative in the 1990s by several Mariazell Railway employees who managed to fetch back the Mountain Line's original locomotive. Power supply Due to its history and early provenance, the Mariazell Railway is run on the unusual voltage of 6.5 kV and frequency of 25 Hz, provided by its own supply from the EVN power company. For the power supply of the whole Mariazell Railway and the region along the line, three 25 Hz multi-phase generators at the Wienerbruck power station were used with an apparent power of 6,600 kVA. This accounts for the single-phase