WestNet follows through on shutdown threat

The state's rail operator - which WA premier Colin Barnett said was obliged to do its own maintenance - stopped trains on the Katanning to Nyabing, Trayning to Merredin, York to Quairading and Tambellup to Gnowangerup lines.

WA transport minister Simon O'Brien responded by indicating the state government would review WestNet's contract.

The move follows repeated funding requests for what WestNet sees as crucial track upgrades.

This month's State Budget and May's Federal Budget did not allocate funding for the work.

Mr O'Brien said the State Government had not had sufficient time to consider the request and likened the closure of the lines to having "a gun held to our head".

But Mr Barnett told the ABC that the state government would not "use taxpayers' money to bail out a private company".

Aspects of the battle mirror the experience in Tasmania, where the rail operator, Pacific National Tasmania, has  spent years calling for substantial state government investment in the below-rail assets.

WestNet Rail had earlier rejected calls for an audit of its performance, including its maintenance record.

The rail operator had earlier described the necessary funding as "cyclical", once-in-a-decade investment that should be borne by the WA Government.

The state's dominant grain handler, CBH, has begun planning to move grain by truck.

It comes as the state sees a surge in grain exports, with CBH having shipped more than 7m tonnes since November, up more than 50% on the same time last year.