Working on ratlike transporter (3,6)

I believe the answer is:

oil tanker

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'transporter' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?

'working on ratlike' is the wordplay.
'working' indicates anagramming the letters.
'on'+'ratlike'='onratlike'
'onratlike' anagrammed gives 'OIL-TANKER'.

Can you help me to learn more?

(Other definitions for oil tanker that I've seen before include "Ship carrying fuel" , "[See] ocean-going vessel" , "Ship carrying "black gold"" , "craft" , "Fuel transport ship" .)

I've seen this clue in The Daily Express.

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