Who says Sau Mail is not packed. Except 2-3 months of monsoon (which is true for all trains in india) there is no availability in this train. Since many decades there are only 2 trains between Jamnagar-Rajkot-Mumbai. Sau Exp is 3rd class fast passenger. And if not so pack why does WR have to run holiday spl between hapa-mumbai and okha-mumbai. I tkink you have not tavelled any time in Sau exp. It takes more than 19 hr to reach mumbai from rajkot and 24 hrs from Porbandar