I think that many of the staff at the station are there to signal the trains are able to leave. Since longer trains have been introduced there must either be a visual system for the train driver to see that the doors are shut and that the train is safe to leave OR there has to be staff there to do that. Eventually there ail be mirrors or CTV or something but in the meantime the trains are 'waved off' by 'hand'. The staff are moved around between stations on the network so might not feel they 'belong' to HOP.