From Wikipedia
To the Liverpool end of Town Green station on the Ormskirk bound side and behind the signal box (now demolished) there used to be a small loop line with a very low white painted station which was the platform used by Royal trains when the Royal family were visiting Knowsley Hall – the home of Lord Derby or attending the Grand National race meeting at Aintree.

Sidings over on the left hand side were used for the Guinness Exports depot. Now long gone.