RapidKL LRT trains were engulfed in smoke twice today following fires  believed to have been caused by a fault in the trains' braking systems.

The first incident occurred at the Setiawangsa Station along the Gombak line  at around 8.30 this morning during rush hour.

The Kuala Lumpur Fire and Rescue Services Department said in a statement that a fire had started beneath one of the coaches due to a brake failure and this resulted in the train being filled with smoke.

Passengers were then evacuated and moved to a different location while firemen dealt with the flames.

RapidKL in a series of tweets during the incident, said a 'burning odour' was detected after which they removed the train from service, adding the problem was later traced to a break fault.

No one was reported injured during the incident.

Four hours later, though, at about 12.20pm another LRT train was engulfed in smoke, this time at the Universiti Station along the Kelana Jaya line.

It is not clear if there was a fire this time. RapidKL later said this train too suffered a break failure.

It said all passengers were safely evacuated from the train which has also been pulled out from service.

Design issue with brakes

In statement issued later, Rapid Rail Sdn Bhd confirmed that the second incident also involved a minor caused by the train's brakes.

"It is a continuation of the four-car trains' braking problem which was first highlighted in February. Both the train manufacturer, Bombardier and the parts maker Knorr Brake Company, have acknowledged that there is a design issue," said Rapid Rail CEO Ahmad Nizam Mohd Amin.

"While working for a long-term solution, our engineers have been attending to the brake callipers of the existing 35 four- car trains by replacing the brake seals. As of today, some 40 percent of the 560 units of brake callipers have been fitted with new brake seals," he said.

"Since being identified, Rapid Rail Sdn Bhd has been conducting special checks on the brake systems of the trains. Being a fail-safe system, any brake failure will result in the trains stopping," he added.

Ahmad Nizam said today's fires were a result of the 'brake dragging issue".

"The liquid discharged due to leakage will cause excessive smoke when hitting the hot iron track. It should be noted that any occurrence of fire is not immediate.

"The train would have stopped and a rescue team would be immediately dispatched to commence efforts to evacuate the passengers.

"In today’s incidents, all passengers were already transferred to rescue trains when the brief fires occurred. Both fires were put off by Rapid Rail rescue team members by using fire extinguishers in the trains," he said.