Rajdhani/Shatabdi/Duro paxs are most disadvantaged as
50% of paxs are paying 150%/140% flexifares and
40% of paxs are paying 110%-140% flexifare
But the facilities are inferior to HS where paxs pay very diluted flexifare and Tejas where paxs pay no flexifare.
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It is true that Tejas & HS are being promoted as compared to Raj/Shat/Duro. That is why introduction of HS on Rajdhani Routes have been mostly avoided so far.