Wolverton’s initial purpose was the repair and maintenance of engines, but before too many years passed the workforce had acquired the skills and equipment to build new engines. The tradition of contracting out the building to other firms continued, even in McConnell’s time, but increasingly Wolverton took on new builds.
I am more of a social historian than railway historian, and I certainly don’tn have any engineering expertise, so I can’t offer any erudition on the subject. One excellent source, for those of you with an interest in this subject, is Harry Jack’s Locomotives of the LNWR Southern Division. Wolverton’s role in this period was huge. Details of the book and its availability can be found here.
The pictures I present here of Bury’s first locomotive designs are taken from Harry Jack’s book.