A Melbourne Cup win would be the icing on the cake for Ed Dunlop.

The English trainer, who flew into Melbourne on Thursday to oversee the final stage of Red Cadeaux's Cup campaign, said winning the race had become one of the biggest challenges in the thoroughbred world.

Red Cadeaux will be lining up for the fourth time after twice finishing second in Australia's most famous race.

He was narrowly denied in 2011 by Dunaden before returning to finish eighth to Green Moon in 2012.

Last year only the Gai Waterhouse-trained Fiorente stood between Red Cadeaux and victory.

Dunlop believes the gelding flourishes when he arrives at Werribee to prepare for the Melbourne Cup.

"I don't know what happens here but he becomes a different horse," Dunlop said.

"He loves it here. He loves the personal attention.

"To line-up four times in a row with the same horse that's not from Australia I don't think will be done again.

"It's testament to the horse, my staff, the owner and the team here that deserve the credit."

In a change of routine, Red Cadeaux arrived in the first shipment of international horses for the carnival on September 27.

Consideration was given to running him in the Caulfield Cup but his weight was fluctuating so it was decided to keep him fresh.

The prospect of running him twice on firm ground was also a deterrent.

Dunlop headed straight from Tullamarine airport to quarantine at Werribee to see Red Cadeaux on Thursday morning.

He said his team in Melbourne, headed by travelling foreman Robin Trevor-Smith, had done a great job keeping Red Cadeaux in top condition.

"He's moving well, his legs look good, his weight is spot on," Dunlop said.

"I can only mess it up, so I'll stay out of the way."

It is almost two years since Red Cadeaux last tasted success in the 2012 Hong Kong Vase.

The horse's owner, Ron Arculli, is a Hong Kong resident but he has been the driving force behind Dunlop's quest to land a Melbourne Cup victory.