Mexico City Metro Line 4 is the fourth line of Mexico City Metro. The line color is aqua blue and it runs from north to south of the city crossing the city center by its easternmost area. In 2019 it had a total ridership of 29,013,032 passengers, making it the least used line on the system.

Mexico City Metro Line 1 is one of the twelve Metro lines operating in Mexico City, Mexico. Officially inaugurated in 1969, it was the first metro line to be built in the country. Its identifying color is pink, and it runs west–east.