What do I do, if I cannot plan my journey in advance?
Though it is always advisable to plan your journey well in advance, there may be times when this is not possible. For such situations, Indian Railways have introduced the Tatkal Scheme in Sleeper Class, AC Chair Class, 3-Tier AC and 2-Tier AC classes in almost all Mail/Express trains. The reservation under this scheme commences at 8 a.m. on the previous day for which the reservation is being sought. Tatkal Bookings is available one day before excluding the date of journey i.e., for journey on 3rd, the booking would be starting at 8 a.m. on 2nd. for further detail click on this link