==Recent and future changes==
The Ankara - Baku train
is expected to start running in August 2019, resulting in the opening to passengers of the (Kars -) Mezra - Karakale TCDD - Kartsakhi RK - Akhalkalaki line.
The 37.4 km İstanbul M11 express Metro line, connecting the Gayrettepe financial district and the new İstanbul Airport, is planned to be completed by the end of 2019. The 27 km İstanbul Airport – Halkali line is planned to be completed in 2020.