January, although avoid any precipitation or wetness (or whatever they call it!) and certainly no dynamic weather!
Birmingham Crewe Modern Timetable (i.e. the one that comes with the 805) Class 323 RR 1Z23 This is a nice railtour run. I played it in May and it was quite enjovable, including the stopover in Stafford (provided that you have many UK DLCs installed).