Henry Dwyer has been on a steep learning curve from the day Caroun entered his stable.

Caroun is one of two jumpers Dwyer trains and the only one to have raced over obstacles this season.

On Sunday, Caroun contests the Grand National Hurdle at Sandown.

Dwyer inherited Caroun when Peter Moody closed his training business and jumps jockey Tom Ryan came to work for his stable.

"I enjoy it," Dwyer said.

"When Peter Moody retired Tommy Ryan was riding work for him and he started riding work for me.

"The horse effectively came with Tommy as a friend of his owns the horse and he'd been riding it, so we took the horse on."

Initially Dwyer didn't have any lofty expectations for Caroun and thought he may be a better steeplechasing prospect.

But the gelding won his first start over jumps for Dwyer and picked up a $20,000 bonus.

Dwyer began thinking of the Grand National and looking at the better class lead-up races.

However it hasn't all gone smoothly.

Ryan came off Caroun at Warrnambool last month when a horse fell in front of him.

He was scratched from a race at Bendigo two weeks later when his float broke down and he didn't get to the track on time.

Dwyer said Caroun needed another start before Sunday's race and he took him to Casterton where he finished fifth behind Danzadoozie on July 28.

"Casterton is pretty tight and the jumps come up pretty quickly and he didn't get the chance to get into a rhythm," Dwyer said.

"Good horses can go there and get beaten but go somewhere else at their next start and win.

"He's raced there twice and failed, so I'm putting it down to that or he lost his confidence after the incident at Warrnambool."

Caroun tackles Arch Fire and Gingerboy, the quinella pairing from two feature hurdle races earlier in the season, along with last-start Bendigo winner Zanteco.

Gingerboy heads the market at $2.80 ahead of Zanteco at $3.80.

Arch fire is third favourite at $6.50 with Caroun a $15 chance.