I have observed in the return direction between Solapur-Mumbai there are a least 6 trains in the SUR-Mumbai stretch which run in gaps of 45min-1hr , which post doubling and other improvements can easily be speeded which probably will end up leading to an odd time of arrival in Mumbai CSMT ( between 12am-3am)
This i guess is preventing CR from speeding up many of trains in this stretch even after doubling