The snapped overhead power line that crippled Perth's rail network last month was the result of substandard training among inspectors, which will cause more emergencies if unchecked, WA's rail union says.
The claim came as the State Opposition said yesterday the Government's order of 15 extra railcars was based on outdated passenger modelling and 30 were needed to keep pace with demand.
Rail, Tram and Bus Union WA secretary Paul Robinson said overhead line inspectors revealed after the Joondalup line emergency on October 3 that none of them had the minimum Australian qualification required to do the work.
The 20-plus inspectors are responsible for maintaining the clips that hold overhead wires in place and making sure the cables have the right suspension and no kinks.
"This is absolutely mind boggling," Mr Robinson said, claiming it was the Public Transport Authority's responsibility to ensure employees working on overhead lines and signalling equipment had the necessary Australian Qualifications Framework certificate.
Train services were halted last month when a 25,000-volt power line tangled around the top of a moving train, causing it to snap and whip across a carriage - the third such incident in five years.
Mr Robinson, a train driver, said after using its union "right of entry" to investigate the incident, the RTBUWA knew what went wrong. He would not reveal specifics in case it jeopardised the official investigation, but said: "The practices (workers) are conducting don't meet required Australian standards."
Transport Minister Troy Buswell said he was unaware of any training deficiency. He would await the outcome of the investigation into the incident "and, more broadly, PTA policy", carried out by two British experts.
"We are not going to hide from anything," he said. "If there are things we have to do differently, we will."
Shadow transport minister Ken Travers said the decision to order 15 new rail cars, taking to 66 the number of cars to be added between 2013 and late 2016, was based on advice from the PTA early last year.
"Then passenger growth was estimated to be 4.5 per cent per annum," he said. "Last year we actually got 9 per cent growth."