Bundesbahn Österreich (BBÖ) took over the Mariazell Railway from the Lower Austrian State Railways, which had fallen into financial difficulties. The first diesel locomotive was tested on the line in the 1930s. This type, later described as ÖBB 2190, was only suited for light passenger trains. The self-powered luggage railcars (series 2041 or ÖBB 2091) were slightly better in performance. After Anschluss in 1938, the narrow-gauge railway, like all Austrian railways, became part of the Deutsche Reichsbahn. During the wartime years 1944 and 1945, there was wartime destruction and damage in many places, especially around St. Pölten. After 1945 After the Second World War, the former State Railway lines became part of the Österreichische Bundesbahnen (ÖBB). The rolling stock was given a new number scheme in 1953. In the following years, there were some alignment corrections on the line. That, and the rebuilding of the rolling stock in the 1950s and 1960s, as well as the changeover to diesel working on the branch line were the furthest-reaching modernization measures undertaken on the railway. Between 1959 and 1962, the original electric locomotives, now known as ÖBB class 1099, were given new, more modern style, bodies, whilst retaining the same traction equipment. The passenger coaches were likewise provided with matching steel bodies. In 1962, the steam engines were replaced by new diesel locomotives, of ÖBB class 2095. The series 399 locomotives went to the Waldviertler Schmalspurbahnen, whilst the remaining steam locomotives were withdrawn from service. In 1981, a speeding train derailed on Buchberggraben viaduct, killing the driver. The locomotive involved (ÖBB 1099.015) was scrapped at the site. In 1984, the last Rollböcke, the more primitive type of transporter wagon using forks to hold the standard-gauge wagon's axles, were replaced with Rollwagen, the more advanced type resembling a wagon with a short stretch of standard-gauge track onto which the standard-gauge wagon is fastened. In 1994, two newly developed electric multiple unit (EMU) trains (ÖBB class 4090) were acquired. In 1995, these were supplemented by some diesel railcars (ÖBB class 5090) for use on lighter loaded services and on the branch line. In the wave of secondary-railway abandonments in Lower Austria, even the Mariazell Railway was affected. Freight traffic using narrow-gauge wagons on the Mountain Line was completely given up, and the short stretch of line between Mariazell and Gußwerk was abandoned in 1988. Freight service still continued for a few years as far