Class 158 Single Variable Rate Sanding (SVRS) Modification

Description

Following the publication of the RAIB report into the Salisbury Tunnel Junction collision of October 2021 and a further collision in October 2024, where two Cl. 158 TfW units collided on the Cambrian line, Northern has begun to assess the case for installation of variable rate sanding (VRS) on the class 158 fleet. VRS systems apply sand to the railhead at a rate proportional to train speed maintaining the optimum 7.5g of sand per metre of rail, improving the wheel/rail interface adhesion far more than current SFRS systems. VRS has demonstrated that safe train stopping distances can be achieved irrespective of the railhead adhesion. Northern's 158 fleet consists of 53 units (Eight of these are three car units and 45 of these are two car units).