Lindsey Smith has no complaints with the barrier Tuvalu drew for this Saturday's Group 1 Railway Stakes at Ascot, but it is a different story with the weather in his old home town of Perth.

Western Australia is in the early stages of a heat wave that will not abate until early next week, with top temperatures of at least 38 degrees expected each day through to Sunday.

That has prompted WA's governing body to push back Saturday's meeting with the first race to be run at 2.05pm local time with the $1.5 million Railway Stakes to be run at 6.09pm.

While Smith is accustomed to the Perth heat, Tuvalu is not and the Warrnambool trainer said how the Group 1 winner adapts in the days leading up to the 1600-metre handicap will determine whether he takes his place.

"If it got super hot, we'd have a discussion whether he went or just try to concentrate on the Northerly Stakes and then back him up in the Gold Rush," Smith told RSN927 on Wednesday morning.

"If he handles this heat the next few days you'll see him. It'll be a bit tricky, but hopefully it drops down to about 36, 37 (degrees) and we take our place."

The Railway Stakes is the first Group 1 of The Pinnacles carnival, followed by the Winterbottom Stakes (1200m, December 2) and the Northerly Stakes (1800m, December 9), with the $1.5m Group 3 Damien Oliver Gold Rush (1400m) to be run on December 16.

Tuvalu is 58kg topweight for the Railway Stakes, a race Smith has won previously with Old Comrade (2001) and Scales Of Justice (2016).

The son of Kermadec has not finished further back than fourth in four runs this campaign, the most recent of which was a narrow third placing in the Group 2 Crystal Mile at The Valley on Cox Plate Day.

Smith is eager to see him embrace the week after the gelding drew barrier four in the field of 16 plus three emergencies, in which he will be ridden by Jamie Kah.

He will start from barrier three if first reserve Casino Seventeen (barrier three) fails to gain a start.

Emerging local star Alsephina drew well in gate seven, but favourite Roots came up with barrier 15, while last-start Flemington Carnival winner Forgot You landed the outside alley.

"I think we're set up OK," Smith said of the draw.