Metro Line 12, at Sonarpada
Line 12 is the Kalyan to Taloja corridor. Sonarpada is the station nearest to Umborli, with Manpada and Hedutane on the same line. For a household without a car, this is the piece that matters most, because it connects the Dombivli East belt into the wider metro network rather than funnelling everything through the suburban railway.
The Katai Naka tunnel
This is the one that changes drive times rather than adding a service. The tunnel cuts through the hill on the Airoli-Katai alignment, which shortens the run west toward Airoli and Navi Mumbai. The developer's own comparison puts the Airoli commute from this belt at 50 minutes before the tunnel and 20 minutes after it.
Treat that figure as the developer's, and drive it yourself at the hour you would actually travel. Tunnels change the distance, not the traffic at either end.
Virar to Alibaug multi-modal corridor
A north-south corridor crossing to the west of the site. Its value here is not the daily commute, it is that it links the belt to Bhiwandi, Kalyan and the Navi Mumbai side without going through Thane.
The bullet train station
A station on the Mumbai to Ahmedabad corridor is planned near Diva, which is the next railhead west. This is a long-horizon item and should be read that way.
The railheads you would use today
Dombivli station and Kalyan Junction are the two suburban railheads, with Thakurli and Kopar Road as nearer halts on the same line. Diva sits west of the site. Nothing about the metro or the tunnel replaces these in the near term.
The honest version
Two of these four are under construction and two are planned. A home bought here today is bought on the current commute, with the infrastructure as upside rather than as the reason. The registered completion date for the first wing is December 2030, so the timelines are at least in the same decade.
Full location detail, including the schools, hospitals and retail within fifteen minutes.