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Comment by Mvhsz | Hacker News Reader

High speed rail could share track with commuter lines in some cases, as acela does in the northeast corridor. And building through the rural parts of the state is generally easier, California essentially decided to only build the rural segment of their high speed rail due to cost.

But in general you're correct that projects requiring new right of way are very challenging and expensive. Especially high speed rail with limited turn radius. Since the article mentioned a low-usage rail link between the cities, I would prefer to see a campaign to increase ridership. Maybe you could incrementally upgrade segments of that route that could support high speed rail.

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Does sharing track ever work? Amtrak already has to share track with freight, and that's why Seattle to Portland is officially "3.5 hours" but the margin of error on that is +hours.

Not from the PNW, but it sounds like amtrak rents track from a freight line to run this route. So it works in the sense that they got something resembling inter-city rail service for a tiny fraction of the capital costs up front.

Even so, I'm guessing that there are options other than $50B of high speed track to improve the route. Maybe there's a few segments of track where a large fraction of the delays happen, and 30 miles of amtrak-owned track would really improve on-timliness. Just getting it from +hours to +minutes might draw some new users.

You cannot share track. Take a look at the ICE lines in Germany. The high speed sections are dedicated, with no level crossings and fencing the entire way to eliminate collision risk.

When a train is going 400kph, you can’t share track.

> When a train is going 400kph, you can't share track.

Correct, you would be traveling at normal train speed on shared track. This is workable in some systems because you can build cheap (relatively) rural segments of high speed rail without needing new right of way through urban areas. Obviously wouldn't work everywhere, and maybe it's not the right solution here. But it is done some places, and places like California are considering building new blended systems [1.

[1] http://www.caltrain.com/projectsplans/CaltrainModernization/...

> High speed rail could share track with commuter lines in some cases

Having ridden those very commuter lines, I can say that is not an option here. They are limited to 40mph along those routes because they follow a very windy path along the shoreline. There have been derailments from trains going too fast.

it's not one of the problems with the us rail system, that the infrastructure is owned by private transport companies?

how could you improve those railways if they are not yours to modify on first place?

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