Another much awaited clarification from CR -The matter becomes more clearer now !!!
All passengers holding valid reserved tickets upto LTT/DR/CSTM in Mail/Expresses/Superfasts and alighting at Kalyan / Thane can travel in Mumbai Suburban trains on the same tickets subject to:-
a....
more... The travel is is uni directional only (PERMITTED IN UP DIRECTION ONLY) in the direction/ travel route of long distance train.
b. The destination travelled by Mumbai suburban EMU should fall at or before the destination point of the respective Mail/Expresses/ Superfasts. (So I presume LTT will be Vidhyavihar n not Kurla)
c. Valid in CR KYN CSTM section only.