Re: I'd like to know..
Lots of rail points here:
"how Corbyn plans to finance any of his nationalisations"
It doesn't have to be cash raised in the normal manner. He could issue Government debt to buy up the private assets in question. This is how the big four railway companies were nationalised in 1948, their shares were exchanged for Government bonds. The risk, as another commentard said, is that the bond markets would [potentially] nuke him from orbit.
Note that issuing debt like this is covering the "defect" between Govt revenue and spending.
"BR was a disaster, chiefly because one uppity union rep could shut down the whole network."
Taking that one point - the messy structure introduced by the 1993 railways act was in part to smash the power of the unions. The upshot was the unions adapted and became very effective at playing one TOC off against another. Perhaps not good at closing the whole network, but good at getting pay improvements.
"[Other european contries have...] Progressive unions that don't strike"
I'll leave this here with no further comment
http://www.theguardian.com/world/2015/may/20/train-driver-strike-paralyses-germany-rail-network
"Ninth walkout in 10 months leaves millions stranded as sympathy for workers involved in industrial action nosedives "
"Tube drivers push a button to open and close doors."
On the Victoria line yes, as it uses Automatic Train Operation. On other lines, this is not true and the driver actually drives as well as operate the doors, etc. Note also that trains need some kind of track side competent operator on board. DLR tunnels were built to modern standards with evacuation walkways but the original tube lines are barely big enough for the train so evacuation is through the train onto the track.
Note also that it's shift work with incredibly unsociable hours and carries a lot of responsibility not to mention route knowledge. I'm not necessarily saying they're right to strike but it's much more than just pushing a button.
"I read somewhere he would fund it by printing money and calling it "QE for infrastructure" or something stupid like that."
http://www.bbc.co.uk/news/business-33884836
"the rolling stock is not so easy."
The original BR rolling stock was split up into three ROSCOs (Angel, Porterbrook, and Eversholt) and sold off. This hasn't generated the competition hoped for. Car leasing is easy, you're buying a commodity product with a 10 year life. Once the initial 3 year lease is up you know there is a market to sell the vehicle into. Rail vehicles are bespoke modifications of a specialised product, aimed at a particular line, with a 40+ year life span. Why would you invest in new rolling stock unless you were certain of it being used, thus making your return over that 40 year life? Even in BR days leasing wasn't allowed unless it was at least as cheap as buying. Buying back the ROSCO stock would be difficult and/or costly.
"What's the situation with the freight train operators"
They are not franchised nor subsidised, providing you don't include implicit subsidy from the occasional building of new chord/link lines for freight operation. These often free capacity for passenger services so it isn't exclusively for the benefit of Freight operators.