There is also 09:24 (SX) Wigan NW to Liverpool that calls at Newton Le Willows, St. Helens Jn, Lea Green, Rainhill, Huyton & Liverpool only. (omitting Earlestown)
There are two trains in the opposite direction.
15:42 (SX) Liverpool - Wigan calls at Huyton, Rainhill, Lea Green, St. Helens Junction, Earleatown then Wigan (omitting Newton Le Willows)
18:31(SX) Liverpool - Wigan calls at all stations to Newton Le Willows then Wigan.
Presumably these exist mainly to retain route knowledge, as they hardly provide a useful service between Wigan and stations Newton Le Willows to Whiston / Huyton. ?