>>54651I think the fact that it's taken eighteen years to build, mostly by volunteers and the trust that built the A1 is nearly £800000 in debt is suggests that another could be built but it would cost a whole lot more if you wanted it sooner.
It was assembled in Darlington, but most of the components had to be built elsewhere. The end of the Steam Age of British Rail saw a lot of the old shops and depots where you could build these locos close and all of the equipment was either scrapped or sold.
The case in point is the boiler on the A1, it had to built in Germany because nowhere in the UK has the facilities anymore.