M2 coach is not a standard term used in Indian Railways. However, there is a mention of M1, M2, and M3 coaches in some sources. These sources suggest that M1, M2, and M3 are the designations for AC Three Tier economy class coaches. The coach position and seat number can be known when the chart of any particular train is prepared.
It is worth noting that M2 is also used as a model designation for a coach bus by Coachwest Luxury Performance.
