Based in Derby , it provides train services in the East Midlands and surrounding areas , chiefly in the counties of South Yorkshire , Nottinghamshire , Leicestershire , Derbyshire , Northamptonshire and Lincolnshire . Based in Derby , it provides train services in the East Midlands and surrounding areas , chiefly in the counties of Lincolnshire , South Yorkshire , Nottinghamshire , Leicestershire , Derbyshire and Northamptonshire .