I have been asked about the end date of the Sunday service this year. Whilst the services show as running until 8th December, all 8 trains have been cancelled from the timetable on every single Sunday from 15th September onwards until the December timetable change. Thus it would appear that this year's last Sunday service will be on 8th September 2019.
It is not yet know when the Abellio East Midlands Railway will start the year round Sunday service, there are a lot of details of the new franchise still to be revealed. Hopefully we will find out in due course.
