RRB Practice 24

Winter fog is one of the most serious operational challenges faced by Indian Railways in the northern part of the country, particularly in the states of Uttar Pradesh, Punjab, Haryana, Delhi, and Bihar, where dense fog from November to February severely reduces visibility on railway tracks and creates hazardous conditions for train operations. During episodes of dense fog, visibility can fall to less than ten metres, making it impossible for a loco pilot to see signals, speed indicators, or track features at a distance sufficient to safely control a train running at normal operating speeds. The traditional response to fog was to restrict train speeds to as low as 30 kilometres per hour on affected sections, accept extensive delays of hours or even days on long-distance trains, and rely on the loco pilot's memory of the route and verbal communication from track-side staff. The Fog Safe Device, developed indigenously by the Research Designs and Standards Organisation of Indian Railways and subsequently refined and commercially produced, represents a significant technological intervention in fog safety. This GPS-based device, installed in the locomotive cab, uses the train's GPS position to determine the train's location on the track and triggers audible and visual alerts to the loco pilot at a configurable distance before every signal post, level crossing, speed restriction board, and other critical track feature on the route. By providing advance warning of upcoming signals regardless of visibility conditions, the device allows the loco pilot to approach signals at a speed that permits timely braking even if the signal cannot be seen until the last moment. The device does not replace the signal system but supplements it by ensuring the loco pilot is mentally prepared and in the correct brake mode well before the signal location. The deployment of Fog Safe Devices across the loco fleet of northern railways has allowed a significant relaxation of the blanket speed restrictions previously imposed during fog conditions, improving punctuality while maintaining safety. In parallel, Indian Railways has been progressively installing automatic train protection systems including Kavach, which provides direct brake application when a train approaches a signal at danger regardless of whether the driver has received the device alert, adding a second layer of protection. The operational procedures for fog working include specific guidelines on headway maintenance between trains, communication protocols between loco pilots and train controllers, and the mandatory reporting of fog conditions by field staff. Station staff, gatemen, and trackmen posted at fog-prone locations are equipped with flare signals and detonators to warn approaching drivers of hazardous conditions. Despite these measures, fog-related train delays and occasional accidents continue to occur, and the investment in technology and training for fog operations remains a priority for the zonal railways of northern India.