[2] After the project suffered various financial reverses in the 1990s and early 2000s, the first three stations were originally scheduled to open in 2007.

[6] At the end of 2021, the Russian government canceled construction due to lack of money, now there will be a tram.

Two more lines running from north to southeast and from northeast to southwest are planned longer-term; the time frame for their construction is undefined.

Construction companies in arrears on their taxes to the local and federal governments offered their services to build the Metro in lieu of payment.

The construction plan was developed many years ago and as the city has expanded and transport needs have changed greatly, critics argue that the initial stations will be of little help in reducing traffic congestion or improving the transportation system.