TOPWEIGHT Purple Gold could keep trainer David Hill's title hopes alive with a win in the third event at Happy Valley tonight. Not that the former Madras-based trainer is concerned about the title battle when champion John Moore is looking odds-on to keep the crown. Hill returns today from a lightning trip to England but said after River Verdon's victory on Saturday: ''The championship has never entered my calculations. I plan ahead for my horses and run them where I think they will benefit best. If I get enough winners, well and good. ''But I won't enter runners or change plans just on an outside chance that I might land another winner or two.'' Even so, long-time stable inmate Purple Gold could spring a modest surprise in the third event where he is not likely to start in the front line of betting. This six-year-old horse has never run over the minimum equitrack trip but has shown a real liking for the surface over 1,400 metres and a mile. He also has a short sprint win to his credit on the grass, at Happy Valley, and can certainly muster speed. Hill legs up stable claimer Raymond S. M. Tam for this conditions race, for jockeys who have ridden less than 250-career winners, and it is always helpful to have a rider who does know the horse. Tam rode Purple Gold in an equitrack mile event in Class Two last time out and was certainly not disgraced in finishing fourth. Clearly this is an easier race with the distance the major problem. There will be plenty of support for Orchestra, the bottomweight prepared by trainer Peter Ng Bik-kuen, who did not come out of the stalls last time for Tony Cruz and cost punters a fortune. He has since trialled impeccably and tonight Victor C. F. Chan gets his chance. The outside barrier of eight may not help and it is likely that Lucky Champ will take up the running. The Wong Tang-ping galloper is a very definite chance over this trip and much will depend on how close Purple Gold is to lead at the turn. If he is within three lengths he could run on down the centre of the course and oblige. The horse does not lack resolution and this is not an awesome field. Electric Power has become a very expensive conveyance and may be less than genuine while Optic Style has not been doing enough to warrant support.