Fully AC suburban train is likely to be a failure just because of very less frequency. With very much difficulty, IRlys shall be able to find a few new slots per day for these ac trains. People want frequent services, they don't like to wait for 1 hour just to avail ac suburban trains.
It may be noted that in Mumbai suburban 12 coach rakes are gradually being augmented to 15 coaches. Since the existing non ac coaches are already running with crushing loads, it would be better if a 1 or 2 ac coaches are provided in all 15 coach suburban rakes to begin with, so that a respectable frequency can be offered to the ac suburban travellers and at the...
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same time all the number of non-ac suburban coaches shall continue to remain in service i.e. there shall be no reduction in non-ac coaches in lieu of the ac coaches introduced. The solitary ac coach may be located near centre of train (i.e. 8th coach) so that there are no hassles of boarding the ac coach in local trains.
If in future, not more services are getting converted into 15 coach ones and the solitary ac coach get very good response, then there is an option to replace first class coaches with ac coaches after considering views of the first class travellers through an extensive survey.