Multiple Hong Kong champion jockey Douglas Whyte has steered Scales Of Justice to an all-the-way win in the Group One Railway Stakes in Perth.

Whyte got the call-up to ride the Lindsey Smith-trained gelding when Paul Harvey was suspended last Saturday when Scales Of Justice won the Group Three R J Peters Stakes, also over 1600 metres,

A week later, Scales Of Justice ($9) was back at Ascot to to score a dominant 2-3/4 length victory over last year's winner, the Chris Waller-trained Good Project ($9) with $4.60 favourite Perfect Reflection third..

It was the second Australian Group One win for Whyte who rode the Waller-trained Moriarty to take out the 2014 Kingston Town Stakes, also at Ascot.

"It's good to get another Group One in Western Australia," Whyte told Sky Thoroughbred Central.

"I was confident at the 1400 metres.

"Lindsey gave me confidence and said it nothing else wants to lead, you lead.

"When I turned for home and pressed the button he had a whole lot of engine there."

Smith said he would enjoy the moment and discuss plans with owner Chris Wells before deciding whether Scales Of Justice would tackle the Kingston Town in two weeks.

"We got Douglas down here and he showed why he's been champion jockey in Hong Kong so many times." he said.

Earlier Damian Lane made a triumphant homecoming to win the WA Guineas (1600m) on Variation ($19) for trainer Stephen Miller.

The Melbourne-based Lane lost his Railway ride when the well-supported Darren Weir-trained Rageese was scratched with a foot abscess.

After being in an awkward position at the top of the straight, Variation came up the inside to beat the $4 favourite Ellicazoom by half a length.

"It didn't look good at the top of the straight but he got the run on the insde," Lane said.

"I'm rapt to be home."

It was big result for Miller who said Variation would now have a spell.

"He was up in class but we had to have a dip at it," Miller said.

"It was great to get his (Lane's) services. It's bloody tremendous."