What are auxiliary systems?

Auxiliary systems are the various support systems on rolling stock (locomotives and railcars) that are not directly involved in propulsion or braking but are essential for the operation of the vehicle and the comfort and safety of passengers or the proper handling of freight. These systems include air conditioning, heating, lighting, toilet systems, communication systems, and power supply systems for these amenities. Air conditioning and heating systems regulate the temperature inside the vehicle, providing a comfortable environment for passengers and crew. Lighting systems provide illumination inside and outside the vehicle, ensuring visibility and safety. Toilet systems provide sanitary facilities for passengers and crew. Communication systems enable communication between the train crew, passengers, and central control. Power supply systems provide electrical power for all of these auxiliary systems. For example, a passenger railcar's auxiliary systems would include the air conditioning that cools the car, the lighting that illuminates the interior, the public address system used to make announcements, and the toilet facilities. A freight car might have auxiliary systems like refrigeration units (for transporting perishable goods) or specialized loading/unloading mechanisms. Proper functioning of these auxiliary systems is critical for ensuring a comfortable and safe journey for passengers and for the efficient and reliable transport of goods.