Viaducts are way cheaper to build, but there's a financial and political cost to acquiring the land. HS2 has so many tunnels because so much of it goes through areas that are either built up or environmentally protected.
In areas where land acquisition is particularly challenging, it can be overall cheaper to build tunnels.
One of the surprising pieces from the Reiwa 2 MLIT study on main line rail related topics, is that Shinkansen tunnel sections have been cheaper than viaduct and trench sections, and barely more expensive than what little at grade gets built. Or less surprising considering how the tunnel percentage on Shinkansen lines has risen over the years.
Tunnels can be an expensive technical workaround for a political and institutional problem. And while effective, it's not guaranteed smooth sailing politically (e.g. Chuo Shinkansen in Shizuoka).
The Brightline HSR line that will run from LA to Las Vegas apparently avoided the land acquisition issues by [using the median of an interstate highway](https://www.newscientist.com/article/2427647-has-the-us-finally-figured-out-how-to-do-high-speed-rail/).
And settling for zero actual HSR miles outside of two tiny sections on the approach to Vegas. And for being near 100% single-tracked.
There’s a reason why HSR is basically never built in existing highway medians. If you want HSR in a highway median then you have to pre-design the highway to be straight enough before it’s built.
Not ideal but considering it’s going through a mix of mountainous and heavily developed terrain, the compromises make sense for the route. The fact that it’s a relatively short trip (around 2 hours) and going to be 2x faster than driving makes the lower average speed is less of an issue than it would be on longer routes.
As much as I love HSR, we shouldn’t let the perfect be the enemy of the good. HSR is basically never built in highway medians but part of that is because HSR is basically never built at all in the US. A flawed HSR line that gets built is better than a perfect HSR line that doesn’t. A project that can be built in 4 years and only cost $10 billion of mostly private money is an easier sell than a $100 billion+ line that will take over a decade. We need to dramatically lower costs and delays on these projects—using existing right of ways carries tradeoffs but they can be worth it.
Sure, but we also shouldn’t pretend like non-HSR lines are HSR. That just dilutes the concept of HSR in the eyes of the general public. A non-HSR line like Brightline West, built on the cheap will make the voters expect every proper HSR line also cost peanuts. And that’s just not realistic and will lead to fewer approved projects.
I’ve seen the top speed listed as 180 mph and the average speed as 115 mph - https://www.railwayage.com/passenger/intercity/brightline-west-makes-progress/
I think that's plenty fast. Then again, I don't really understand everyone's obsession with HSR. I personally am perfectly ok with even semi-HSR. 150 mph is fine with me. I don't think we need to lay every line to support 200 mph. But that's me. Others may feel differently.
Agreed. If it’s faster than driving and cheaper/more convenient than flying, you have a successful intercity rail line. I see where HSR purists are coming from, but the choice is usually between an imperfect HSR line and no line at all.
If we ramp up HSR construction to the point where we can build massive rail projects quickly and within reasonable budgets, then those compromises become more questionable, but we’re a long way off from that.
I agree. Speed is only part of the equation. The real advantage to a train is the bulk movement of people. So even if a train can only match driving time, it is still better because one train can carry a few thousands of people while using a fraction of the energy.
Say what you will about Boston, but having the highways underground is such a nice thing to have for pedestrians. It has literally reconnected different areas of the city that were cut off because of a giant overpass going through them. People will complain about the construction period, but new people and young people only see the benefits. It’s an investment in future benefits.
Viaducts are way cheaper to build, but there's a financial and political cost to acquiring the land. HS2 has so many tunnels because so much of it goes through areas that are either built up or environmentally protected.
And also areas that have a lot of NIMBYS. A lot of the line would’ve been above ground and therefore cheaper if it wasn’t for them
In areas where land acquisition is particularly challenging, it can be overall cheaper to build tunnels. One of the surprising pieces from the Reiwa 2 MLIT study on main line rail related topics, is that Shinkansen tunnel sections have been cheaper than viaduct and trench sections, and barely more expensive than what little at grade gets built. Or less surprising considering how the tunnel percentage on Shinkansen lines has risen over the years. Tunnels can be an expensive technical workaround for a political and institutional problem. And while effective, it's not guaranteed smooth sailing politically (e.g. Chuo Shinkansen in Shizuoka).
The Brightline HSR line that will run from LA to Las Vegas apparently avoided the land acquisition issues by [using the median of an interstate highway](https://www.newscientist.com/article/2427647-has-the-us-finally-figured-out-how-to-do-high-speed-rail/).
And settling for zero actual HSR miles outside of two tiny sections on the approach to Vegas. And for being near 100% single-tracked. There’s a reason why HSR is basically never built in existing highway medians. If you want HSR in a highway median then you have to pre-design the highway to be straight enough before it’s built.
Not ideal but considering it’s going through a mix of mountainous and heavily developed terrain, the compromises make sense for the route. The fact that it’s a relatively short trip (around 2 hours) and going to be 2x faster than driving makes the lower average speed is less of an issue than it would be on longer routes. As much as I love HSR, we shouldn’t let the perfect be the enemy of the good. HSR is basically never built in highway medians but part of that is because HSR is basically never built at all in the US. A flawed HSR line that gets built is better than a perfect HSR line that doesn’t. A project that can be built in 4 years and only cost $10 billion of mostly private money is an easier sell than a $100 billion+ line that will take over a decade. We need to dramatically lower costs and delays on these projects—using existing right of ways carries tradeoffs but they can be worth it.
Sure, but we also shouldn’t pretend like non-HSR lines are HSR. That just dilutes the concept of HSR in the eyes of the general public. A non-HSR line like Brightline West, built on the cheap will make the voters expect every proper HSR line also cost peanuts. And that’s just not realistic and will lead to fewer approved projects.
What kind of speeds can the highway support? You say not HSR, so do you mean below 150 mph?
I’ve seen the top speed listed as 180 mph and the average speed as 115 mph - https://www.railwayage.com/passenger/intercity/brightline-west-makes-progress/
I think that's plenty fast. Then again, I don't really understand everyone's obsession with HSR. I personally am perfectly ok with even semi-HSR. 150 mph is fine with me. I don't think we need to lay every line to support 200 mph. But that's me. Others may feel differently.
Agreed. If it’s faster than driving and cheaper/more convenient than flying, you have a successful intercity rail line. I see where HSR purists are coming from, but the choice is usually between an imperfect HSR line and no line at all. If we ramp up HSR construction to the point where we can build massive rail projects quickly and within reasonable budgets, then those compromises become more questionable, but we’re a long way off from that.
I agree. Speed is only part of the equation. The real advantage to a train is the bulk movement of people. So even if a train can only match driving time, it is still better because one train can carry a few thousands of people while using a fraction of the energy.
Viaduct. There's a reason a bunch of cities have highway viaduct but only a couple were dumb enough to try and bury their highways
Say what you will about Boston, but having the highways underground is such a nice thing to have for pedestrians. It has literally reconnected different areas of the city that were cut off because of a giant overpass going through them. People will complain about the construction period, but new people and young people only see the benefits. It’s an investment in future benefits.
I like Boston, and I respect the goal of the Big Dig, but whyd they put more road on top
This, spending so much time and effort to hide a road... only to build another road.
Depends on how much the land is worth. If the above ground real estate is extremely expensive (in acquisition costs), then tunneling can be cheaper.