It might be possible that, with the construction of the Thomson Line (TSL) and the hypothetical Seletar Line, the new NSL will become the 'rapid' commuter railway serving the north-south corridor, while the TSL and the Seletar Line, along with the portion of the NSL from Marina Bay to Ang Mo Kio, will be the slower rapid transit lines that serve this corridor.
It might be possible that the original North-South Line (NSL), from Jurong East to Ang Mo Kio, and then on to Marina Bay, might be realigned into one continuous line via this branch line, and upgraded to some kind of commuter railway line for the north-south corridor (personally I'm already beginning to regard the portion of the NSL from Yio Chu Kang to Jurong East as more of a commuter railway line and less of a rapid transit line).
In regards to the Ang Mo Kio branch line, if they are really making it an express line, then I do have reason to believe that they are going to realign the North-South Line to follow the alignment of this new branch. I'm splitting this discussion off from the Circle Line thread, so as not to spam up that thread.
