When De Little Engine started his spring campaign trainer Danny O'Brien was looking at another race on Caulfield Cup day.

But as numbers began to fall, the six-year-old has found himself in Saturday's 2400m-handicap.

The gelding was first emergency when the field was finalised on Tuesday and gained a start with the scratching of New Zealand mare Fanatic following a suspected spider bite.

O'Brien had Saturday's Coongy Cup in mind for De Little Engine as part of a long range plan towards winning the Lexus Stakes at Flemington on Derby day and gaining a start in the Melbourne Cup.

"We didn't expect at any stage that he was going to get a run in the Caulfield Cup," O'Brien said

"We're certainly not complaining as in any other year we wouldn't even be an emergency.

"He's come up in really good order. He's a really seasoned, older style of stayer now.

"He's gone through the grades over the last couple of seasons and carried big weights.

"Now that he's getting up in grade he's getting right down in weight which is a big help as he's only a little horse."

O'Brien won the Caulfield Cup in 2007 with lightweight Master O'Reilly who found his way into the race by winning the Herbert Power Stakes the week before.

De Little Engine will be ridden by Ben Thompson, one of three apprentices riding in the race for the first time.

Thompson found out De Little Engine had made the field while he was riding in barrier trials at Seymour on Thursday.

"I can't thank Danny O'Brien, his team and connections enough for the opportunity for the ride," Thompson said.

"It's going to be a huge thrill."

Ben Allen has been riding for 18 months and partners the Ciaron Maher-trained Pemberley.

The 17-year-old still claims a 2kg allowance in the metropolitan area.

"I wasn't expecting to be riding in a race like this at this time of the year," Allen said.

The youngster sees it as a great opportunity to be mixing it with the best riders from around Australia and overseas but knows it will be a tough test from barrier 17.

"I can't do much about it," he said.

"I'll look to slot in midfield or maybe a bit worse and hopefully they might spread out a little bit."

New Zealander Michael Dee, apprenticed to Mick Price at Caulfield, said it was a dream to gain a ride at his home track on the Maher-trained Set Square.

"When I first came over here I didn't think I'd be riding in these big races but it's gone from strength to strength and hopefully it keeps going," Dee said.

"It's just a dream really."

The third of Maher's runners, Jameka, will be ridden by senior jockey Nick Hall and is the reigning Caulfield Cup favourite.