Southern Railway (SR) is one of the eighteen zones of Indian Railways. It is headquartered at Chennai and operates across the states of Tamil Nadu, Kerala, Andhra Pradesh and the union territory of Puducherry. The origin of the Southern Railway can be traced back to the Madras Railway formed in 1845. Southern Railway was created on 14 April 1951 by merging three state railways, namely, the Madras and Southern Mahratta Railway, the South Indian Railway Company, and the Mysore State Railway. Southern Railway maintains about 5,081 km (3,157 mi) of railway lines and operates 727 railway stations.

Indian Railways (IR) is a statutory body under the ownership of the Ministry of Railways of the Government of India that operates India's national railway system. As of 2023, it manages the fourth largest national railway system by size with a running track length of 104,647 km (65,025 mi) and route length of 68,426 km (42,518 mi) of which 60,451 km (37,563 mi) is electrified. With more than 1.2 million employees, it is the world's ninth-largest employer and India's second largest employer.