Crack nation turned to reveal liquid transporter (4,3)

I believe the answer is:

tank car

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

'liquid transporter' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?

'crack nation turned to reveal' is the wordplay.
'to reveal' indicates a hidden word.
'turned' is a reversal indicator.
'racknat' can be found hidden inside 'crack nation'.
'racknat' written backwards gives 'TANK-CAR'.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

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