> Most train platforms are maxed out at well below 10 cars (Caltrain is 6 cars)
> a perfectly run commuter train system is _just_ barely comparable with a regular 6-lane freeway
Also look at any major route in Britain, like Manchester to London, no 6-lane highways anywhere in sight.
You are comparing some weak-ass train with a giant highway. It's easy to extend a rail platform to accomodate more train cars - you just need to knock down a few buildings in a local area. Now try widening a 3-lane highway into a 6-lane, that could be hundreds of building and NYMBY's across three cities.
Allegedly the Eurostar, which links Paris to London, does:
"Inter-Capital" sets consisting of two power cars and eighteen passenger carriages. These trains are 394 metres (1,293 ft) long and can carry 750 passengers: 206 in first class, 544 in standard class
I can't find info on the upcoming HS2. However I do testify that extremely long trains are common in Eastern Europe, Russia, India, etc. they might not be high-speed but they do move a lot of people at once.
20 car trains are a distraction here the important correction is 150 passengers per train is way low. 250 is common and going higher (e.g. double decker) is pretty easy if you need to
Also look at any major route in Britain, like Manchester to London, no 6-lane highways anywhere in sight.
You are comparing some weak-ass train with a giant highway. It's easy to extend a rail platform to accomodate more train cars - you just need to knock down a few buildings in a local area. Now try widening a 3-lane highway into a 6-lane, that could be hundreds of building and NYMBY's across three cities.