Two thirds of rail lines out of Norwich station in Norfolk will be disrupted at the weekend with trains replaced by buses for parts of the journey.
Many lines in Norfolk will be disrupted by maintenance gangs
Network Rail has planned engineering on routes from Norwich to Great Yarmouth, Sheringham and Lowestoft on Saturday and Sunday, and to London on Sunday.
Services to Cambridge will run as timetabled while Central Trains to the north will be disrupted in Yorkshire.
Passengers on the King's Lynn to London line face disruption around Cambridge.
Train services affected by disruption will include services run by One Railway, Central Trains and First Capital Connect.