Protectora de la Infancia) on September 25, 2020, the metro system was back to 100% operation. Timeline Rolling stock The Santiago Metro currently operates 9 models of rolling stock: two models (the AS-2002 and the AS-2014) are steel-wheeled, while the others are all rubber-tyred. The NS 74 and NS 93 stock are based on the MP 73 and MP 89 stock of the Paris Metro respectively, while the NS-88 and NS-2007 stock are based on the FM-86 and NM-02 stock of the Mexico City Metro respectively. All rubber-tyred stock is preceded with the acronym NS (for Neumático Santiago); likewise, all steel-wheeled stock is preceded with the acronym AS (for Acero Santiago). The number representing each type of rubber-tyred and steel-wheeled rolling stock is the year of design of a particular rolling stock, not year of first use, similar to the practice in the Mexico City Metro and Paris Métro. Currently the NS-2007, NS-2012, AS-2014 stock and a number of the NS-93 stock are retrofitted with air conditioning. In September 2012, the NS 2012 trains went into service on Line 1. These trains are the first to be built with air conditioning. On November 2, 2017, the line 6 entered revenue service. This line utilizes the AS-2014 (Acero Santiago 2014) which are the most modern stock of the system , being the first model in the system that are driverless. However, in the first and last car there is a control panel meant to control the train when necessary. It is also the first with security cameras, energy obtainment via overhead rigid catenary, and evacuation doors at the front of the first and last car (with an evacuation ramp for people on wheelchairs) as well as on the sides of each convoy. They are also the second to be built with air conditioning, and the third with LED lights. The line that they operate in is also the first in revenue service with platform safety barriers, followed by Line 3 opened in January 2019. Stations In bold are transfer stations. In grey are stations projected or currently under construction. Art in the Metro The Santiago Metro incorporates a number of works of art in the design of its stations. The station Universidad de Chile has a giant mural created by Mario Toral and represents the history of the country. Other pieces of art are in Baquedano (featuring modern art and a