The RMT are for nationalisation for idealistic reasons. The Labour party was born of the railway unions in Doncaster, as well as all the other worker movements at the time. Chiefly a protest against the division between the high pay of the ruling class, and the grinding poverty of workers at the time - although railwaymen up until the 1960s were always relatively well paid.
Having said that, there is a bigger division between rich and poor now, with a few percent owning most of the wealth, and the under 35s have most of the debt.
The RMT are a bit of an anachronism, most railway workers are not avid socialists, but they are still strong because of safety risks of doing the job and have a long and proud history of defending terms and conditions - not always to the benefit of the rail industry as it does not work in isolation within transport! Other modes are notorious for anti-union practices, especially road haulage where much of the workforce has been and is recruited from the forces - whose mentality has always been against popular organisation of workers against their 'superiors'.
The RMT have now cut its ties with the Labour party - who now support much of the short contract, sweat shop globalisation methods and hold companies up in high esteem who do much to undermine workers rights either here or abroad.
The RMT also objects to the profits taken by private companies for what is essentially little risk - most of the TOCs (which the exception of one or two like Chiltern) are not very entrepreneurial and are really just management contracts - expensive ones at that.
When the railways were built, at least 4 times more value was had by the nation from them as the entrepreneurs got back in share values and dividends. These days, because of competing modes, it is almost impossible to make profit except for maybe freight, and a limited amount of intercity and commuter lines, but lines are supported for 'positive externalities'
Its noteworthy that some of the TOCs share prices are going down, as the ORR have granted access agreements to the new open access companies like GC and have turned down NXEC's request to run services to Lincoln.
http://www.guardian.co.uk/business/2009/jan/30/east-coast-mainline-shares
The TOCs would argue the open access operators cherry pick services and TOCs are left with more regulation and little opportunity to exploit the market in the same way.
This isn't far removed from nationalising the lot, leaving the state with naturally loss making services and inviting private companies to come in and cherry pick profit making ones. Which might sound 'bloody stupid', but the reality is private companies will only get involved where there is profits to be made or massive, almost no lose, state guarantees. No private company goes into business to make a loss - it could neither raise the money for investment or service its debts - that's how capitalism works.
With the railways of Europe and forced to have 'open access', again for this reason I can't really see it being nationalised 'properly', because of the cherry picking problem, which would be even worse than it is now.
Nevertheless it doesn't mean loss making services have no 'value'. The majority of benefits (and disbenefits) from transport tend to be outside the fare box.
While A level students are taught nationalisation is bad (except for banks it appears) and unions practices are restrictive and stop the correct working of the market - this under a Labour government - I can't see there being much of a case for nationalisation.
Having said that, while the economists and politicians have their own ideas about globalisation and opening markets to competition (a right wing capitalist ideology) it appears in the down times workers may have other ideas, with spreading protests and riots across the globe and in this country to protect jobs and conditions. Essentially protectionism with the usual arguments against markets and capitalism: Myopic, non reflection of externalities (positive or negative), exploitation of workers, materials and animals in the quest for the cheapest product/service, doesn't respect cultures or social need, transfers wealth to the rich. And no doubt the usual arguments will go against socialism and protectionism: Inefficient allocation of products and services, is less efficient at generating wealth, leads to less choice.
In short, the organisation of wants and needs will always be open to emotive arguments and at some level, protection of ones own interests, whether you are a customer, worker, investor, manager or entrepreneur.
