How many rakes does a train require?-
If there are no complications because of 3-way rake-sharing and so on, it is easy to figure out the number of rakes that are needed for any particular train service. Assuming 1-2 hours a day to allow for late running, and perhaps 4-6 hours a day for cleaning and maintenance, a rake is used perhaps 16 hours a day for short distance trips, and 18 hours a day for long trips. From this, one can estimate the number of rakes given the total journey duration.
Up to 8 hours : 1 rake (unless it is a night train)
8-17 hours : 2 rakes
17-26 hours : 3 rakes
26-36 hours : 4 rakes
36-46 hours : 5 rakes
46-56 hours : 6 rakes