>>1020543It's getting a second ring "so called third interchange corridoe (?)", with some auxiliary tangential lines.
A Russian person on 1chan explained me why it is third interchange corridor, but I'm not really sure if it's the reason that mostly between the first and the second metro rings there is this recently passenger train ring that also appears on metro maps, but he also said something along the lines that the first interchange corridor is the large cluster of transfer stations inside the existing ring line, so the ring line itself is the second interchange corridor.
