Business secretary Vince Cable is at the site of an £82m development that will create hundreds of North East jobs.
The new factory, at Hitachi Rail Europe's plant in Newton Aycliffe, will be built by Darlington-based contractor Shepherd.
The firm will create 150 new jobs to construct the plant and secure hundreds more across the region's supply chain.
Vince Cable and Transport Secretary Patrick McLoughlin will open the development.
More top news
It is the final weekend to say goodbye to the Great North Snowdogs in Gateshead.
Former Newcastle captain Alan Shearer is an ambassador for the NSPCC and is urging victims of the football abuse scandal to call its hotline
Middlesbrough MPs are joining in the UK-wide celebration of small businesses.