is Tamil Nadu (Tri weekly)
123/124 is Telangana (Bi weekly)
Both TN and Telangana used to run in same slot.
15/16 is Grand Trunk
139/140 is Ganga Kaveri which used to depart from Madras Beach
17/18 is Andaman
137/138 is some train between NZM and BSP, I don't know which current train is this.
Please note that how less halts did TN, GT and TS had.
Most importantly TN took 29:10 hours from NDLS to MAS and TS took 22:45 hours from NDLS to SC. This 1979 schedule can even put MAS and SC Rajdhani to shame.
What is the use of WAP-7, LHB and 130 MPS when WDM-2 with ICF Rake and 110 MPS was far superior ?
Source- Southern Railways Time Table belonging to my Grandfather.