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Comment by alexpotato | Hacker News Reader

Whenever I see comments about how slow public projects are these days, I think about this documentary: https://www.pbs.org/wgbh/americanexperience/films/race-under...

It's a PBS special about the history of the Boston subway (which was one of the first in the nation).

To give you an idea of what construction safety was like back then, they would routinely encounter gas lines, cut them WITHOUT turning off the gas, and keep working.

Obviously, this led to lots of explosions but also very quick construction. If you are optimizing for speed over safety/environmental/etc it's pretty surprising how quickly you can build something.

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Safety usually isn't the problem. It's the public notice periods, feedback collection, final notices, environmental impact studies, lawsuits over whether the environmental impact studies were sufficient, possible need to get the government to invoke eminent domain, studies over which potential version of a project needs the least disruption, and so forth.

Near where I live is a bridge over a river that needs replacing. The county had to study three different ways to do it, weighing environmental impact, traffic disruption, total cost of each option, and so forth.

The planning and regulatory portion of the project is easily 75% of the timeline, and that's for a fast one due to the condition of the bridge itself. If it were less urgent, it would have likely taken even longer.

Meanwhile collapsed Minneapolis I-35W bridge (remember that? Gusset plates, etc?) got replaced in something like 7 months, they picked a colorado company and started construction very quickly. Of course a half dozen local construction companies filed suit but the bridge was built really fast.

Right next door to that bridge are three other projects: a cliff/dirt collapse/erosion/retaining project that kept the river parkway closed for like 4 years, and two bridges being reconditioned that have been closed for 3. Those went through the "normal" channels.

A friend of mine was on I35W, about a half mile or mile before where the bridge collapsed, and had to take an exit to get off the freeway. Lots of small quirks of fate slowed down his trip that day just enough that he wasn't over the portion that collapsed when it went down.

I think a part of the difference is that the federal government provides funds for maintenance of the interstates, and the sheer volume of traffic that was being re-routed down other roads that weren't really intended for the extra traffic (adding lanes to 94 certainly helped some).

Shame that it requires a catastrophe to see what we can really do when it needs doing.

> they would routinely encounter gas lines, cut them WITHOUT turning off the gas, and keep working

That's still done today, evidently! A few months back, there was a small gas leak in my neighborhood. When they knocked on my door to say they'd be working in the area, the repair crew leader was kind enough to indulge my questions.

I asked them if my gas would be shut off. They said no, they do the work while the gas is still on!

And they must have been cutting into the gas line because they replaced a section that ran under the street. They used a backhoe to dig huge holes on both sides of the street and then fed a flexible pipe through.

Here's a video about something kind of similar: https://www.youtube.com/watch?v=UCMs__ZnOfA

I'm sure today's techniques are different and much safer, so I don't think it negates your point that they used to do risky stuff.

> I asked them if my gas would be shut off. They said no, they do the work while the gas is still on!

My understanding is that most "last mile" gas lines are pretty low pressure and low flow. On purpose, so that if theirs a leak they aren't releasing massive amounts of gas into the atmosphere in a hurry, so the concentration doesn't raise to dangerous levels.

Then when they are working on the lines and in those pits to make connections, they have detectors to tell if there's a dangerous build up, and ventilation to ensure it doesn't happen anyway.

The system generally being low pressure is why sometimes during really cold periods when demand is high, the gas company has to adjust field regulators to increase flow so that demand can be met. They normally run at low enough flow that if everyone's furnace and stove and water heater all run at once, the lines would effectively run out of gas.

For some anecdotal comparison on the pressure on the main lines on the other hand: Recently a gas main near me sprung a leak. It sounded like a low flying jumbo jet right overhead while I was over a kilometer away. The pressure on those must be absolutely bonkers.

part of the issue in 2024 is that the ground is a lot fuller than it used to be, so it takes more time. In some cases, like in New York, step one is figuring out where any of that stuff even is, because for privately owned infrastructure the maps are not public or even shared with government, and in some cases the infrastructure is so old that the maps are not accurate, if they are even available.

we now build projects to relocate utilities (so that you don't have to shut down a subway line to replace an adjacent water pipe) but that stuff is costly and everyone is prepared to sue the other in case of a mess-up. but there is a lot of the physical version of tech debt; New York is still replacing wood and lead piping, for example.

The New York City subway was built by:

- digging down a small amount (in contrast to London where they dug DEEP under everything else)

- rerouting ALL of the existing pipes etc (you can find photos of the rerouted gas lines)

- Putting in the subway

- Putting everything back

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