I think that Mumbai CST to Panvel or Kalyan are certainly achievable, and over time the whole Mumbai urban system could be done, maybe not the outer green extensions (over 120 route miles) but the core would be good
The Central line of the Mumbai Suburban Railway is a public transit system serving Mumbai, Maharashtra, India. It consists of 24 stations from Chhatrapati Shivaji Maharaj Terminus (formerly Victoria Terminus) to Kalyan Junction. The entire line is at grade. It has section of quadruple track starting from Chhatrapati Shivaji Maharaj Terminus and ends at Kasara, Roha, Lonavala and Khopoli in Maharashtra. The Central line in Mumbai consists of three major corridors, which bifurcate as they run into suburban satellite towns. Two corridors (one local and other through) on Central Railway run from CSMT to Kalyan Junction (55 km),[3] from where it bifurcates into two lines – one running up to Kasara (67 km) in the north-east and the other running up to Khopoli (61 km) in the south-east. These two corridors constitute the 'Main' Line. The Central main line shares one station with the Western line at Dadar. They consist of a fleet of DC as well as dual-powered EMUs. The major car sheds on this line are at Kurla and Kalva. There are fast and slow locals here for suburban service. Slow locals halt at every station, while fast locals halts vary between Byculla, Dadar, Kurla, Ghatkopar, Vikhroli, Bhandup, Mulund, Thane, Diva, Dombivli and Kalyan Junction. All services plying beyond this junction run slow. Trains usually start from and terminate at important stations. Busy Dadar Station Two long distance express trains entering busy kalyan junction Kalyan locomotive shed's exclusive wcam2 locomotive hauling express train CST - Kalyan stretch can be made with busy EMU as well as express operations.
Will we get a note "Press E to sit on passenger seat" when we point at a window or roof of the train?
Question will be answered if the route sees the light of day. But the roof scene was a thing of the past. Unique question though.