Unfortunately I think that a lot of the cleanliness problems with Northern units are caused by the people who travel on them. If you are ever on a train out of Leeds/Manchester/Liverpool/Blackpool/York/Hull/Newcastle/Sheffield, etc. on a Friday or Saturday night, you will witness some apocalyptic scenes of drinking, spilling, urinating, defecating, projectile vomiting, feet on seats after walking through the aforementioned substances, etc, etc. I'm not just talking about young people here....all too often the culprits are middle-aged couples, or groups of middle-aged men or women out 'on the lash'. The TransPennine Lager Trail - formerly known as the TransPennine Ale Trail - is a particular problem and has now over-spilled onto the Calder Valley Line, with Hebden Bridge becoming a popular destination for these binge drinking gangs of both genders. It would take an extremely thorough and very expensive cleaning regime to deal with the aftermath of this sort of behaviour.