Timeline of the NBR

1842 The Edinburgh & Glasgow Railway opens.

1843 Prospectus first issued for the "The Great North British Railway".

1844 The North British Railway Act receives Royal Assent.
Construction starts almost immediately.

1845 The Edinburgh & Hawick Railway is authorised
The E&HR and the Edinburgh & Dalkeith Railway are both taken over by the NBR.

1846 The Edinburgh Berwick line opens.

1859 Sanction to build the remaining Waverley route from Hawick to Carlisle.

1859 Buy out of the Port Carlisle Railway, giving access to Carlisle.

1860 The Border Counties Railway is acquired
This is partially open but still under construction.

c.1860 East Coast Joint Stock partnership
This partnership with the Great Northern Railway (GNR) and North Eastern Railway (NER), agrees to a pool of rolling stock to be shared on Anglo-Scottish expresses.

1862 The NER achieves running powers between Berwick and Edinburgh.

1862 Amalgamation with The West of Fife and The Edinburgh, Perth & Dundee Railways

1862 Waverley route completed.

c.1865 Amalgamation with the Edinburgh & Glasgow Railway.

1870 The Tay Bridge Act receives assent.

1873 The Forth Bridge Company founded with four partners - NBR, NER, GNR & the Midland Railway.

1873 The Forth Bridge Act passed.

1876 Through trains between London St Pancras (Midland Railway) & Edinburgh Waverley commence.
This becomes possible when the Midland opens the Settle & Carlisle line.

1878 The Tay Bridge opens.

1879 The Tay Bridge disaster.
After the Tay Bridge collapses, all work on the Forth Bridge is abandoned.

1880 The NBR becomes joint owner, with the Caledonian, of the Dundee & Arbroath Railway.
The objective is a route to Aberdeen in anticipation of the increase in traffic volume once both the bridges are opened.

1881 The New Tay Viaduct Act passed.

1882 Work on the new Forth Bridge commences.

1888 The New Tay Bridge opens.

1889 The West Highland Railway Act receives assent.

1890 The Forth Bridge opened.

1892 Rebuilding of Waverley station commences
Rebuilding is completed in 1902.

1894 The West Highland Railway opens.

1896 The West Highland Extension Act passed.

1897 The NBR succeeds in stopping the NER's through running to Waverley.

1898 The NER resumes running into Waverley.

1901 The West Highland Extension to Mallaig opens.

1908 The West Highland Railway absorbed by the NBR.

1923 With Grouping, the NBR becomes a part of LNER.

1969 The Waverley route closed.

Acknowledgements

Thank you to Richard Barron for the above information.