Yes, I know these problems. Which is why I mentioned attaching a couple of coaches in the busy season, not as a permanent basis till such lacunae are rectified.
Power may not be much of an issue for mixed rakes as only one EOG is used. It may pose some problem with full AC rake with pantry. Presently, P7 power capacity is being ramped up by 500 HP. It may be in line with providing more power with HOG. With 100% track electrification in sight, next couple of years might see most trains with electric power end-to-end.
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more... platforms at major stations do have required length from where most popular and prestigious trains operate. What I suggested was attaching couple of extra coaches to such trains only in busy seasons when wait list turns into regret.