How did you get 15 trains to Mumbai? There are only 3 trains but only one is exclusive Bangalore Mumbai. What you are seeing in time table are passing through trains which do not touch Bangalore or Mumbai or both cities and with no seats quota for SBC Mumbai pax. Surprisingly all three trains are run by central railway. Nothing by SWR!.
What is the use of doubling and electrification if trains take 24 hours to cover 1100 kms?