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Don't all shout at once if that is a stupid suggestion lol. Going from location of the station rather than from substantial knowledge of the goods traffic there.
In the west mids your best bets are Tamworth, Nuneaton and Water Orton. Nuneaton is quite hemmed in though and Tamworth has the inconvenience of being on two levels, then Water Orton the inconvenience of a rubbish service level.
I speak as a passenger not a spotter but Nuneaton must take every crown in the box - in ten minutes waiting for the Coventry train I once saw at least five container trains go through!
Otherwise Preston, which has the added bonus of being a Freightliner crew changeover point so you can get up close and personal with stopped heavy trains.