Looks like a new express service between Newcastle – Hartlepool – Middlesborough - only stopping at Thornaby, Hartlepool & Sunderland only - every 2 hours.

North East

Newcastle – Hartlepool – Middlesborough (Durham Coast) Introduction of an additional semi-fast service between Middlesbrough and Newcastle (anticipated in the summer) once platform infrastructure work by Network Rail is complete at Hartlepool station.

https://www.northernrailway.co.uk/timetablechange