If this is referring to the date shown in service mode runs, that day is reflecting the date that particular service is based on, not the current date. At least that is what was said in a pervious post reporting the date not showing today's date.
This is how I understand it too, and different services have different dates too, so this is more than likely the case here.
Matt P has mentioned in multiple streams (I know a lot of people don't/can't watch them) that you can actually in most cases go look up the timetable for the rail company and you will see all the services which were run, and that match the ones replicated in the route. It is one of the reasons for example on East Coastway some of the services are saying they go to Hastings what thats not in the route, but the service that is being replicated in game goes to Hastings IRL.
