The suburban system of CR is the most complex with many diversions/junctions etc, (It is 240 kms long, 4 times bigger than WR suburban stretch of BCT-Virar, Dahanu is not counted here)
Diversions start right from Sandhurst Road 1.2 kms from CSTM
CSTM-SION is a 4 line stretch
At Kurla 2 more lines get added (harbour line) which then branch off towards Panvel
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Vidyavihar 5/6th lines of LTT add up making it 6 lines till Thane
From Thane the number of mainlines reduces to 4, But becomes 6 again due to 2 lines of Trans-harbour route (Thane-Vashi)
Thane-Diva is 4 lines, Diva is junction point where 2 lines go towards Panvel
Diva-Kalyan is 6 lines once again, With the last 2 lines reserved for freight operations and are pure AC while the mainlines are still DC
Kalyan-Kasara, Kalyan-Karjat is 2 lines stretch (3rd line for both the stretches is planned)
Karjat-Khopoli is single electrified line
Trains from Kalyan towards Vasai Road branch off from Kopar (which has two stations one on lower level and another upper level)
Trains like LTT-NZM/LTT-GKP SF have to divert from 6th line to 4th line from LTT and again beyond Kalyan it is just 2 lines and with the ever present EMU's lying ahead or trailing makes smooth operations much more difficult...