In Scotland it consisted of;

North British Railway 
Great North of Scotland Railway 

In England it consisted of at least;

North Eastern Railway
Great Northern Railway
Great Central Railway
Great Eastern Railway

The new company was managed at local level; for example managers of the former North British Railway became mangers of the routes of the NBR within Scotland and the routes of the GNSR. Managers of the NER became managers of the railways of the north east of England of both the NBR and NER. Other areas were similarly controlled as before. There was an overall mangement layer and co-ordination of designing and building new engines.

In England the line owned the routes running up the east coast from London, including the route now known as the East Coast Main Line. In Scotland lines approached Edinburgh from Carlisle in the west and Berwick in the east. The naming of the company was not particularly appropriate; the company owned the former Mallaig Extension Railway which has the westermost station in Britain, Arisaig, on its route. The company also owned many stations and lines in Glasgow which is in the west of the country.

The company had a number of alternative slang names such as the "Late and Never Early" Railway.

The company was nationalised in 1948 and became part of British Railways.