Tough two-year-old Diomedes will continue a racing partnership which has covered three generations and more than half a century when he runs at Doomben.

Diomedes, who runs in Saturday's GH Mumm Handicap (1600m), is trained by Bryan and Daniel Guy for retired Sydney businessman Tony Valos.

The Guys have lost count of the winners they have had for Valos who has remained loyal to them for decades.

Valos' best horses recently include Dienekes who won 11 races and three-time Doomben winner Athena Mana Mou.

He also has a place in history as the owner of Rose Of Athens who gave champion Brisbane jockey Mick Dittman his first Sydney winner.

Bryan Guy said Valos first had a horse with his father Ray Guy at Rosehill in the late 1960s.

"Tony gave Dad an expensive horse by super sire Star Kingdom which had cost the then large amount of six thousand guineas. It had been with another trainer and had problems with its hooves," Guy said.

"Dad won some races with it and Tony has stuck with us ever since. When Dad died in 1992 Tony kept sending his horses to me.

"And now Dan is also training it is three generations of Guys who are indebted to Tony for his support.

"Luckily, most of Tony's horses have made it to Saturday city races and that will continue on Saturday with Diomedes."

Guy said Diomedes, a last-start midweek Doomben winner over 1350m, would be suited by the 1600m.

"But they haven't missed us at the weights and he has a bad barrier so luck will play a part," he said.

Diomedes will carry equal topweight of 58kg with Robbie Fradd to steer him from barrier 10.