Nash Rawiller is always in demand with Sydney's biggest racing stables but his willingness to help out a country trainer can pay more dividends at Warwick Farm on Wednesday.

Rawiller has rides for leading Sydney trainers Chris Waller, Gai Waterhouse, John O'Shea and Bjorn Baker in a typically strong midweek book for the jockey.

But it his mount Fort Sumter in the theraces.com.au Handicap for Muswellbrook trainer Pat Farrell which might turn out to be his best.

Rawiller won on Fort Sumter at Warwick Farm on March 20 and since then he has led the way with Group One wins during the main fare on offer during the Sydney autumn carnival.

So far he has won the Ranvet Stakes and BMW on New Zealand mare Silent Achiever as well as the Galaxy on Tiger Tees.

Rawiller will be lining up for another slice of Group One action on Saturday without forgetting the importance of a city win to a bush trainer like Farrell.

"The poor country trainers don't get much of an incentive to come to town," Rawiller said after Fort Sumter lumped 60kg to his Warwick Farm win.

Fort Sumter goes up in class on Wednesday but drops 3kg for his victory over Foxbat and Bracidame.

The sprinter will also have to contend with a wide barrier but he races better at Warwick Farm than at any other metropolitan track with two wins and a minor placing in four starts.

Tommy Berry will have his only ride for the meeting in the race when he partners first-up winner Chatham House for Hawkes Racing.

Berry is mourning the loss of his twin brother and fellow rider Nathan Berry.

As well as carrying obvious sentimental support, Chatham House is expected to be well fancied in the betting after Berry rode her to an easy win at Canterbury.

Warwick Farm was rated in the heavy range during a Tuesday morning track inspection.