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Its not like that sir ..
Actually TN gets the outmost priority in every zone due to its avg speed of 67 kmph ..
So if ur train is late then it will be overtaken by TN because if made to run behind Goa then its delay will increase ..
And then at destination instead of one train they will be having 2 trains...
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in delay catrgory ..resulting hard to find vacant platform at ndls..
..so this happen ..
Also.goa arrival.is 06:20 and if its overtaken by TN it means that its running late ..

All 3 trains already late from JHS ie. GT, Goa and TN but mostly only Goa gets trolled, 12779 has good slack between MTJ to NZM even covered 45 minutes delay at MTJ on my trip to NZM.
Also if you are filing RTI there is another case of such unscheduled overtakes happening in SCR which I know ie. in VSKP BZA sector where a SF 12717 is overtaken on unscheduled basis by 18047 a M/E and sometimes also by 18463 which is a M/E too.
You can go through some...
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posts in 12717 train blog forum and use the search term 18047 or Amaravati.

Your point is for current scenario.
But if one LHB SF (permitted 130 MPS) can cover CNB-NDLS within 5 Hrs than why not other.Schedule need to be revised as per speed. So many train rached station RT or Before but these train stop at station till priority train not departed. Its Actually caused delayed.
Train 22412 depart from NDLS at 15:50
Train 12878...
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Depart from NDLS at 16:05
Both train has 130+MPS and same running time 5Hrs but 12878- RNC Garib rath always overtake 22412 before CNB due to that 22412 getting delayed always.
It is only obe example...It is totally Discrimination did by IR.

It is usually ( I say 'usually', because in some cases it might be due to more political reasons, or the priority assigned to a zone for a train) not discrimination, but more about operational feasibility. I had learned a few things about his from a team at my college that worked on signalling system for Madras suburban network. They used to interact regularly with controllers during their work and had a good insight into how it works.
For trains that pass through multiple zones or divisions, usually the crew links, loco links, working time table, overtakes, crossings etc, are planned much in advance. So, when a train is running late, all the zones...
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the train passes through, will have to adjust their operations accordingly to accommodate the delayed train. For example, if 2 trains are headed towards CR and SCR from ET ( which is in WCR) via NGP, and both trains are running late/ or one of them running late, and if CR is able to accommodate a delayed train better than SCR, then priority will be given to the SCR bound train as any delay in that train would 'probably' result in a higher delay later on as SCR won't be able to accommodate it.
Usually we see some slack times at zone/division changeover points to accommodate such things, but the controllers are provided a delay margin for each train, using which they can associate priority to a train over the other.
Of course, some times, trains' controlling is also affected if it is a popular train on the route or through the zone ( i.e., one that the general public pay attention to) in which case, those particular trains are paid some more attention to ensure that a good image is retained in the public.
For the most part, controllers usually are just concerned with managing the trains in their sections, given the trains' TT requirements by all the zones/ divisions on their routes.