As far as i can remember , earlier both Chambal / Shipra were crawlers & they used to travel via Howrah - BDC - BWN route . Departure time from HWH was around 3:15 pm. Even though now these trains are of SF category with reduced travel time but still not a single day they manage to run timely. Now what is the meaning of this SF tag when they don't ever run on time ?? Should these trains be degraded to normal mail/ exp trains ??