During British Times, Mixed Passenger Trains used to run. 20 Coaches, 9 for Freight & 11 for Passengers(SL-5; II-3; 3A-2; 2A-1) Now in current time of 22-24 coaches, SER & SER can do 10 Freight Car + 12-14 Passenger Cars.
For example:- 12859/60 can have this combination. L-EOG-F1-F2-F3-F4-FSLR-UR-UR-UR-S1-S2-S3-S4-S5-S6-PC-B1-B2-B3-A1-A2-F5-F6-F7 = 24 coaches, Freight-7, SLRD -1; Sleeper-6; 3AC-3; 2AC-2; UR-3; P-1; EOG-1;