The team looking after three-time Melbourne Cup runner-up Red Cadeaux would like rain before Saturday's Australian Cup.

Showers are forecast in Melbourne on Sunday and Robin Trevor-Jones, travelling foreman for English trainer Ed Dunlop, said the ideal scenario would be a soft track at Flemington on Saturday.

However Trevor-Jones knows that unless there is a freak storm, a good track will be on offer.

"It slows the others down a bit and brings a bit of stamina into play," Trevor-Jones said.

"He goes better on it and lets himself down more.

"It would be ideal if we can get a bit of soft ground, especially at a mile-and-a-quarter (2000m)."

Red Cadeaux, on his fifth trip to Melbourne, is in top order for the first of a possible three runs in Australia.

Following Saturday's Australian Cup the plan is to head to Sydney for The BMW (2400m) at Rosehill on March 28 and the Sydney Cup (3200m) at Randwick on April 11.

"He's in good nick," Trevor-Jones said.

"We've got to pray that he pulls up in good order and then we can head up to Sydney."

"Nothing is written in stone with him. He's Red Cadeaux and he'll let us know."

With track manager Mick Goodie predicting Flemington to be in the good range, Red Cadeaux is an easing $13 chance with Happy Trails firming to $4.60 favourite.

Melbourne Cup winner Protectionist opened the week as the Australian Cup favourite but with solid support for Happy Trails is now the $5 second elect.

Happy Trails was successful in the spring in the Mackinnon Stakes over Saturday's course and distance.

Trainer Paul Beshara said ideally he would have preferred Happy Trails to have had one more run in the lead-up but is fit and well.

"If you look at it he would be the most consistent weight-for-age horse in Australia at this time," Beshara said.

"There's a lot of pressure coming on you when favourite, but who cares, we're there to win.

"He doesn't know what price he is."

Protectionist is aiming to join Fiorente, Makybe Diva and Let's Elope by winning the Australian Cup following their Melbourne Cup victories.

Craig Williams will be having his third ride aboard the stayer and said a return to Flemington after a first-up sixth at Caulfield was more suitable.

"I'm sure he's looking forward to getting back to Flemington, away from the difficulties of the Caulfield circumference, and last time he was at Flemington he saluted," Williams said.

"Let's hope we have the same result."