CITYFLO 650 signalling is a CBTC system designed by Bombardier Transportation. It makes use of bi-directional radio communication between trains and wayside equipment, as well as true moving block technology, to control train operation. Trains report their position via radio, and a wayside signalling system provides movement authorities to the trains via a radio link. Transit lines using the system Transit lines using the Cityflo 650 system as of February 26, 2014 include the following: In revenue service Seattle Tacoma Int'l Airport, SeaTac, USA Sacramento Int'l Airport, Sacramento, USA San Francisco Int'l Airport, San Francisco, USA McCarran Int'l Airport, Las Vegas, NV, USA Phoenix Int'l Airport, Phoenix, USA Dallas/Fort Worth Int'l Airport, Dallas, USA SEPTA Subway-Surface Trolley Lines, USA Heathrow Int'l Airport, UK Gatwick Int'l Airport, UK Line 1 and Line 6, Madrid Metro, Spain Yong-In ART, South Korea Wenhu Line, Taipei, Taiwan Line 3, Shenzhen Metro, China APM Line, Guangzhou Metro, China Line 2 and Line 3, Tianjin Metro, China Purple Line, Thailand Klang Valley MRT, Malaysia Line 5 and Line 15, São Paulo Metro, Brazil M5 and M7, Istanbul Metro, Turkey Bangkok Gold Line feeder system, Thailand Munich Airport, Germany Under construction BTS Yellow Line Monorail (EBM), Thailand BTS Pink Line Monorail (NBM), Thailand Dubai Int'l Airport, United Arab Emirates King Abdulaziz Int'l Airport, Jeddah, Saudi Arabia King Abdullah Financial District Monorail, Riyadh, Saudi Arabia Metro Tunnel (Sunbury Dandenong Line) - Melbourne, Australia MRTA Pink Line and Yellow Line, Thailand Line 7, Delhi Metro, India Sungai Buloh–Serdang–Putrajaya MRT line, Malaysia Line 5 Eglinton, Toronto, Canada Bukit Panjang LRT, Singapore Test tracks These dedicated lines are used to test compatible rolling stock: Pittsburgh Test Track, USA Kingston Test Track, Canada References Train protection systems Vehicle telematics