There has been another incident involving a Transperth gas bus in Perth this morning.
Passengers at Victoria Park station were given a scare about 8am when they were ordered off the gas bus as smoke started billowing from the undercarriage.
Two gas buses have gone up in flames in the past three months, but Transperth does not believe this morning's incident was related.
Spokeswoman Claire Krol said the smoke originated from the brakes, which stuck as the driver pulled into the station about 8am.
"It was a gas bus, but it was just a problem with the brakes," she said.
"The brakes stuck and caused a bit of a smoke. With the design of the vehicles, the smoke goes through the undercarriage and out the back.
"We're pretty confident that it's completely unrelated."
A Department of Fire and Emergency Services spokeswoman said firefighters attended the scene but were not needed.
Mr Krol said the bus had been taken out of service for inspection.
"The bus had pulled in and was stationary, so the brakes must have stuck as he was pulling in," she said.
"We have a mechanic looking at it now."