In the context of Indian trains, SL stands for Sleeper Class. It is the most common and widely used coach class code used by Indian Railways. Sleeper Class is a budget-friendly coach and the cheapest mode of travel, accommodating a large number of passengers. It is a non-air-conditioned coach with 72-80 berths, usually 8 berths in each compartment. The Sleeper Class coaches can be quite noisy and crowded. Bedding is not always included in the fare, and the availability of food and beverages may vary depending on the train.