The Bernina line of the Rhaetian Railway is the highest crossing of the Alps by a railroad and is largely an open line. The highest station is Ospizio Bernina at 2253 meters above sea level. In heavy snowfall and particularly windy conditions, individual scheduled passenger trains are preceded by so-called track ploughs, which can throw snow from the track up to several centimetres below the top of the rails. These plows of type Xk # 9141 to 9147 were built by Stadler between 1966 and 1988. They can be used in both directions of travel. The plows at the front and rear are permanently mounted, the one in the middle of the vehicle can be raised and lowered hydraulically, which is done via radio remote control from the driver's cab of the pushing traction unit. For this purpose, a railroad service employee sits next to the driver with the remote control. Regional train 4656 on line R19 from Tirano to St. Moritz with the "Allegra" ABe 8/12 # 3505 and the track plow Xk # 9143 (built 1968) arrives at Ospizio Bernina. The track plough is usually used between Poschiavo and Pontresina, where it is removed or placed in front.