Show no enthusiasm for a month on the railway (5)

I believe the answer is:

decry

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'show no enthusiasm for a' is the definition.
I can't tell whether this defines the answer.

'month on the railway' is the wordplay.
'month' becomes 'dec' (Dec is an example).
'on' means one lot of letters go next to another.
'the railway' becomes 'ry' (abbreviation).
'dec'+'ry'='DECRY'

Can you help me to learn more?

(Other definitions for decry that I've seen before include "Disparage, regard as unimportant" , "Run down" , "Belittle or disparage" , "Derogate" , "Pull to pieces" .)

I've seen this clue in the Evening Standard.

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