Railway pioneer from south then opens out (10)

I believe the answer is:

stephenson

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'railway pioneer' is the definition.
The definition suggests a singular noun which matches the answer.

'south then opens out' is the wordplay.
'south' becomes 'S' (abbreviation).
'out' is an anagram indicator (out can mean wrong or inaccurate).
'then'+'opens'='thenopens'
'thenopens' anagrammed gives 'tephenson'.
's'+'tephenson'='STEPHENSON'

'from' acts as a link.

Can you help me to learn more?

(Other definitions for stephenson that I've seen before include "man of note" , "Loco inventor" , "George --, rail pioneer" , "Loco engineer" , "Train man" .)

I've seen this clue in The Telegraph.

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