(CNN) -- Passengers, angry about slow service, took out their frustration on trains in Sao Paulo, Brazil, bashing windows and damaging at least 17 train cars Tuesday, an official told the national broadcaster.
The passengers were furious that some trains had stopped moving Tuesday morning, Conrado Grava de Souza, operations director of the Sao Paulo Metro, told Agencia Brasil.
The triggering device to open one of the train's doors malfunctioned causing one of the trains to stop. Passengers used emergency buttons to get off the train and began walking on the tracks.This caused other trains to stop, further slowing service, Souza said.
An estimated 150,000 people were disrupted by the interruption in train service, Souza said.
Later in the day, the 17 damaged trains were back in service.
Journalist Luciani Gomes contributed to this report.