The UK railway network is indeed expanding and the most impressive thing are the usage figures (for both passengers and freight carried). Over 1.2 billion passengers in 2007 - highest since the demobilisation in 1946 and far higher than the "good old days" of the 20s and 30s. Even more impressive when you consider that the network is about half the size of back then.
The white heat of British railway growth is shown clearly in this 2007 study by the TOCs themselves - http://www.atoc-comms.org/admin/userfiles/10 YEAR GROWTH REPORT-1.pdf
Anyway, back to the issue of newly reopened lines:
Telford Railfreight Terminal, Shropshire (re-opened line from Wellington to Donnington)
Ebbw Vale Line, South Wales (re-opened line from Cardiff to the Airport there)
The white heat of British railway growth is shown clearly in this 2007 study by the TOCs themselves - http://www.atoc-comms.org/admin/userfiles/10 YEAR GROWTH REPORT-1.pdf
Anyway, back to the issue of newly reopened lines:
Telford Railfreight Terminal, Shropshire (re-opened line from Wellington to Donnington)
Ebbw Vale Line, South Wales (re-opened line from Cardiff to the Airport there)