Rail travellers can pass on payment (7)

I believe the answer is:

tollbar

This could be a double definition.

'rail travellers' is the first definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I can't see?

'can pass on payment' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe there's an association between them I don't understand?

I've seen this clue in The Times.

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