Are you suggesting that the WAG member for Anglesey was spending this money to placate the Plaid voters?
It was a manifesto commitment :
A Plaid Cymru Government will:
Prioritise creating better links, both road and rail, from the North, the West and the South Wales Valleys to Cardiff.
Continue to support the restoration of full public ownership of the rail system.
As Plaid went into coalition govt from 2007-2011, and as Plaid support is mostly in the North and West, this manifesto commitment appears to have been delivered, for the North at least.