Original sentence: Thirteen stations run under ground while the remaining ten are surface stations
Edited sentence: 20 people were killed and several wounded.After that accident, automatic traffic lights were installed in all the lines.At Tasqueña it links with the Mexico City Light Rail to Xochimilco.It commutes with Line 7 at Tacuba, Line 3 at Hidalgo, Line 8 at Bellas Artes, Line 1 at Pino Suárez and Lines 8 and 9 at Chabacano.It starts at the border of the Federal District and the State of Mexico and ends in the city south.It used to be served by NC-82 and some NM-83 trains.Line 2 was the scene of the worst accident in Mexico City history on October 20, 1975, when a crash occurred between two trains at the Viaducto Station.One train was parked at the station picking up passengers when it was hit by another train that did not stop in time.Thirteen stations run underground while the remaining ten are surface stations.This line was temporarily served by a NM-02 train with landscapes and images of Mexico City