The writer to talk on English railway figures of speech (7)
I believe the answer is:
imagery
'figures of speech' is the definition.
(I've seen this before)
'the writer to talk on english railway' is the wordplay.
'the writer' becomes 'I' (the person who is writing these clues).
'to talk on english' becomes 'mage' (I am not sure about this - if you are sure you should believe this answer much more).
'railway' becomes 'ry' (abbreviation).
'i'+'mage'+'ry'='IMAGERY'
Can you help me to learn more?
(Other definitions for imagery that I've seen before include "something easy to see?" , "statues etc." , "Figures of speech" , "Visual symbolism" , "The use of colourful language to make pictures in the mind" .)