Boring intro from Doors track (3)

I believe the answer is:

dry

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'boring' is the definition.
(dry can mean dull or boring)

'intro from doors track' is the wordplay.
'intro from doors' becomes 'd' (I am not sure about this - if you are sure you should believe this answer much more).
'track' becomes 'ry' (abbreviation for railway).
'd'+'ry'='DRY'

Can you help me to learn more?

(Other definitions for dry that I've seen before include "Alcohol-free" , "Desiccated" , "Juiceless" , "Waterless" , "Decay in timber" .)

I've seen this clue in The Times.

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