/blog/post/3716478 - The NSG 2 of Naihati and NSG 3 of Bandel is becoz of this
And regarding Sealdah, actually it's revenue has also increases significantly but becoz of terminal change of trains like Akal takht exp, Ananya exp, etc from Sdah to Koaa, it has shared a part of it's revenue with Kolkata
Also Howrah will not be able to match the level of new Delhi IMO ever, the prime reason is the huge number of Rajdhani, Shatabdi class premium trains originating from NDLS