Many thanks for your comprehensive reply.  As you can see I'm still learning the ABCs of the train industry.  It's never been particularly important or seen as strategic in Ireland and my experience of it elsewhere is limited.  

To the outsider it also appears as a very expensive and inflexible infrastructure with a lot of externalities which need to be factored in - although I have no idea of how roads compare in terms of costs per passenger and tonnes of goods carried.  

I am concerned at the carbon intensity of all of our current modes of public and cargo mass transport and would be interested in discovering how roads, rail, ships and air compare in this regard.  Most of the growth, in recent years, seems to have been in air transport (or is this an Irish phenomenon?) and I am concerned at the reasons for this and on how sustainable this will be in the long term and what the best alternatives are.

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