The most common and most likely answer to this crossword clue is the 7 letter word TRUCKED
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Buddy explains!

The straight part
We know that "carried by wagon" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case carried by wagon = trucked.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TRUCKED mean?
TRUCKED verb- To drive a truck: Generally a truck driver's slang.
- To convey by truck.
- To travel or live contentedly.
- To persist, to endure.
- (film production) To move a camera parallel to the movement of the subject.
- To fight or otherwise physically engage with.
- To run over or through a tackler in American football.
- To fail; run out; run short; be unavailable; diminish; abate.
- To give in; give way; knuckle under; truckle.
- To deceive; cheat; defraud.
- To tread (down); stamp on; trample (down).
- To trade, exchange; barter.
- To engage in commerce; to barter or deal.
- To have dealings or social relationships with; to engage with.
- Transported by a truck.