In the context of Indian Railways, GS stands for General Seating, which is a type of second-class unreserved coach. Almost every train in India, including Mail/Express trains, has at least two GS coaches - one near the locomotive and one at the end of the train. The General Seating coach is an unreserved coach, which means that anyone with a General/Unreserved ticket purchased from a counter can travel in those compartments. These tickets are usually cheaper than reserved tickets, making them a popular choice for many budget-conscious travelers. However, since there are no assigned seats in this coach, passengers often have to stand for long hours or sit on the floor. It is not uncommon to see passengers crammed together, with luggage and belongings taking up valuable space.

It is important to note that GS can have different meanings in other contexts. For example, GS can also refer to the Georgia Southern Railway, which operates as three segments of track in Georgia, or the Southern Pacific class GS-1, which was a class of conventional 4-8-4 "Northern" type steam locomotive operated by the Southern Pacific Railroad.