Second metro carriage removed in Mexico City

Mexico City workers and volunteers removed the two metro carriages wrecked on Tuesday after an overpass collapsed over a busy highway on Monday night.  At least 24 died and 79 were injured in one of the deadliest incidents in the history of the city's subway system, which is among the world's busiest. 

Earlier on Tuesday, authorities vowed to make an independent investigation to find the causes that led to the accident.  All the structure of the damaged line will undergo new inspections in the coming days to determine the quality of the materials and the construction conditions.