The Swiss began standardising some types of goods wagons at an early stage. They were then also procured by all private railways in order to improve repairs and spare part stock-keeping. They included closed goods wagons with a 4.5 m wheel base and a frame length of 7.10 m. Later, the wheel base was increased to 5 m in order to improve the running characteristics. In this form, high numbers of the wagons that were given the K2 designation were procured by SBB.
