Transport group of juvenile interest (5,3)

I believe the answer is:

train set

I'm a little stuck... Click here to teach me more about this clue!

'juvenile interest' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'transport group' is the wordplay.
'transport' becomes 'train' (train is a kind of transport).
'group' becomes 'set' (both can mean a collection).
'train'+'set'='TRAIN-SET'

'of' is the link.

Can you help me to learn more?

(Other definitions for train set that I've seen before include "Toy with rail track" , "little loco with this?" , "A child might play with this" , "Model tracking" , "Toy railway" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.