In your term 22109 should also not get stoppage at Kalyan that too Starting from LTT at afternoon NON-PEAK hours at 14:30 ?
16/36km term does not work for Highly density place like Mumbai where No comparison exist between Mumbai and any Non-Metro city.
Population of this 36KM surely might be greater then the 150km area's Population in Non-Metro cities.
Still I may...
more... agree with you if this train starts after 14:00. Its Starting time Makes it Unpractical, Difficult and costly affair.
Also consider all the aspect, practicality. Does it Practical to you that travel by Mumbai local at PEAK HOUR 8:00am from Kalyan and get down at Kurla with Language ?
PRACTICALLY it is Difficult for Passenger from Kalyan to catch train from Ltt, TECHNICALLY, This train stops every day at Thane or Kalyan Outter due to Godan Exp. and LOGICALLY, if 22109 (Best train in Cr) can get stoppage at Kalyan then Why not 12542 ???