Trains are unbeatable for inland freight between limited destinations, but don't make much sense for current day commuting or traffic patterns.
There is a notable exception that might distort techie perception on this issue: BART. It implements many of its own standards, even down to track gauge. But it is absolutely an outlier (standardised track gauge, ironically, being the USA’s main contribution to the development of the railways, which it was otherwise late to).
Almost everywhere else has rather interchangeable infrastructure and a lot of trans-national businesses.
https://en.wikipedia.org/wiki/Track_gauge_in_the_United_Stat...
It was a pretty staggering achievement to switch over with so little disruption, and had such rapid, obvious benefits that it kind of ended the notion that keeping entrenched separate gauges could have any merits that outweighed their disadvantages -- it's really the event that made standard gauge the de facto standard.
Things would have taken a generation longer without it, because this was just a plainly capitalistic decision that proved itself essentially instantly.
(Nearest modern equivalent: iMac having no floppy drive and USB)
Nah, this is a UK absurdity because they UK decided to privatise their railways in the worst possible way - every single part (rail infrastructure, operations, rolling stock) was privatised in a local monopoly manner. The rolling stock owners could lease to multiple different operators, so there was some limited competition on that front (probably eviscerated by the need for the ROSCOs to have a profit margin, on top of the fact that there were 10 of them, which meant reduced economies of scale both at acquiring but also maintaining those trains).
They're currently trying to nationalise some parts, after already nationalising the infrastructure (because people died due to bad maintenance due to misaligned incentives - maintenance doesn't bring profits).
But other than that, rolling stock leasing mostly exists in freight.
https://en.wikipedia.org/wiki/Rolling_stock_company
> trains are actually not only mass produced (e.g. by Bombardier)
But yes, trains of all types are mass produced by companies such as Alstom (which were already massive and also bought Bomboardier's train arm), Siemens, Stadler, etc. They can be customised (size, features, etc.), but e.g. the Alstom Metropolis line of metro trains can be found all over the world.
But admittedly that comment was mostly my brain blipping while creating that sentence by settling on the old, broader definition of "Europe" where we used to be significant and that I sometimes use when talking to Americans, hence the subclause clarification about the UK within it.
The point I was getting to is that outside the USA (which definitely has nationally-specific rail vehicles like Amtrak and BART) things are broadly commoditised and relatively off-the-shelf, both in the rail-specific hardware sense and in the wider construction sense.
I don't think there is anything particularly different between building a road and building a railway line in terms of construction skills, and indeed where major roads and rail in the UK are concerned there's at least half a dozen or so major construction firms doing both, right? Clancy, Balfour Beatty, Octavius, Eurovia, Babcock etc. (and those are mostly just names I remember seeing out of train windows)