From Graces Guide
Bute Docks at Cardiff
1839 Increasing agitation for proper dock facilities led Cardiff's foremost landowner, John Crichton-Stuart, 2nd Marquess of Bute, to promote the construction of the (West) Bute Dock, designed by Admiral William Henry Smyth which opened in October 1839.
1841 Just two years later the Taff Vale Railway was opened, following much the same route as the canal.
1855 Construction of the new East Bute Dock from 1855, built by Thomas Cubitt's firm,
1850 Opening of the new dock resulted in coal supplanting iron as the industrial foundation of South Wales, with exports reaching 2 million tons as early as 1862.
The Cardiff Railway came into being to service Bute Docks, to provide facilities for the traffic to and from the Docks. The railway was only 11 miles in length, a fact which belied its importance, since it provided both the Taff Vale Railway and the Rhymney Railway, inter alia, with access. 
1886 The Bute Dock Company was incorporated to take over properties from the late Marquis of Bute.
Sources of Information
-  Wikipedia
- The Stock Exchange Year Book 1908