It is a very interesting question. Few of the writers mentioned that it depends on the loop line but its not true as Indian Railways operates freight trains and Passenger trains both on the same tracks and loop lines are constructed by keeping in mind of a freight train which is generally a 60 wagon train so loop lines can easily handle a 24 or 28 coach passenger train.
Let us know why the length of the passenger trains in India is limited to 24 coaches:-
- Indian locomotives can pull maximum of 24 coaches easily to run at MPS( max. permissible speed). If the number of coaches will be incrrased , acceleration will be slow and train will take more time to reach at mps. That is why most of the trains running at 130 kmph or above have 16–20 coaches only ( excluding exception). Passenger train locomotives are specially designed for the speed.
Note: WAP-5 & WAP-7 locomotives are well known for the speed and used in passenger trainswhereas WAG-9 is for tractive effort and used in Freight trains ( off links excluded).
2. Length of the platforms is designed to handle 24 coaches only .Few major stations have platforms for 26–28 coaches but majority are made for 24 coaches only.
These two are the major factors responsible for this cap of 24 coaches but it doesn’t like running 25 or 26 coaches will effect alot.
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