The devil is always in the detail. Business case. Politics, finance, engineering, and timing.
The Metro came at the right time. Engineering is the least of the issues now. Post COVID nobody knows how the finances are going to pan out. Shapps can make all sorts of encouraging noises now, but ultimately it will be national financial priorities that determine what gets done and when.
This initially looks to be one of the easiser projects to deliver, and relatively it may be.
South East Northumberland has changed a lot since the line was last used for a passenger service running into Manors. Then it was coal mines, rows of colliery wagons and pit heaps all around. No coal mines today, no colliery yards, and most of the pit heaps have been landscaped out of recognition. New roads and private housing developments have transformed the region. Anyone who has not been there for 50 years woud find it hard to recognise the place.
There's the potential market all but proved, just needing some figures to fill the gaps.
The trackbeds are mostly still intact, except for running into Blyth itself. It's mostly level ground so there are some level crossings that are likely to provide conflict with traffic on major roads.
50 years ago most folks lived near the old stations and walked or used bikes. Today they're more dispersed and use cars - on those new dual carriageways. Providing parking space is likely to be challenging if passengers are to be attracted from their cars and fill enough trains to make the business case.
I note it's intended to be served by DMUs. I'd have thought electrified from the start and continued to Metrocentre would be a sensible bolt on option to any plans.