Why Pneumatic Tubes Suck

Whether you know them as the "magic bank tubes" or the high-speed veins of a hospital, pneumatic tube systems are the unsung heroes of mechanical history. In this episode of Dirt Nap City, we are taking a deep dive into the pressurized world of pneumatic tube technology—the original "instant message" that moved physical objects at the speed of sucking air.

The "Whoosh" That Changed Everything

Long before fiber-optic cables and digital attachments, the world relied on the satisfying thwump of a canister being sucked into a vacuum. We explore how these systems evolved from simple Victorian-era mail delivery into the complex, computer-guided networks that still keep modern hospitals and banks running today.

Why Does This Technology Still Exist?

In an age of drones and digital transfers, it’s easy to assume that pneumatic tubes are relics of a steampunk past. However, the reality is quite the opposite. We look at the unique physics—balancing air pressure and vacuum suction—that makes this the most efficient way to transport biological samples, secure cash, and sensitive documents across massive facilities.

In this episode, we cover:

• The Golden Age of Tubes: From the massive postal networks of New York and Paris to the ambitious (and slightly terrifying) "pneumatic subways."
• Modern Marvels: Why hospitals are the biggest investors in pneumatic technology in 2026.
• The "Cool" Factor: Why humans are biologically programmed to find the sound of a pneumatic tube canister incredibly satisfying.
• The Future of High-Speed Transport: Is the Hyperloop just a giant, human-sized pneumatic tube? We break down the connection between classic air-driven pipes and the future of travel.

Perfect for History Buffs and Engineering Nerds

Whether you are a fan of industrial history, a mechanical engineering student, or just someone who misses the excitement of the drive-thru bank teller, this episode is for you. We’ve packed this 40-minute deep dive with fun facts, engineering insights, and a look at the "hidden" infrastructure that makes modern life possible.

Don’t forget to subscribe! If you enjoyed this episode, leave us a review and tell us about your favorite "tube memory." Do you remember the canisters at the department store, or did you work in a lab with a complex matrix of pipes? We want to hear from you!

Keywords: Pneumatic Tube Systems, Industrial History, Engineering Podcast, Vacuum Transport, Hospital Logistics, Mechanical History, Hyperloop Technology, Urban Infrastructure.

Transcript

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SPEAKER_01 0:05

Good morning, Kelly. Hi, Alex. How are you? I'm doing good, man. I I I'm I'm kind of not firing on all cylinders in my podcast voice, but I'm gonna do my best. Well, let's do a dead end today. Ooh, I love those.

SPEAKER_02 0:20

You know, my mom doesn't love those. Uh really. No, she her she likes to listen to this show on her morning walks, and dead ends are too short. They don't they don't fill up her morning walks.

SPEAKER_01 0:32

Uh well, you know what? You know what, uh, Maxine, if you're listening, why don't you just double up and listen to two dead ends, even if it's a repeat? Just throw it up there again. Or just listen to it twice. Yeah, yeah. You know, it's kind of like seeing a movie twice. You sometimes get things the second time that you didn't get the first time. Oh, I see. Alex was the good guy and Kelly was the bad guy. I didn't I didn't see that coming. Yeah, you didn't see it coming. Yeah.

SPEAKER_02 0:57

Well, a lot of things that we talk about on Dead Ends are things that we talk about like when we were kids running, you know, riding around with our parents and things like that. Yeah, riding segues. Looking out the window. And one of the things I like to do when um when there was errands that you know you're in the car and there are errands to to run. Um, one of the things I like to do is um believe it or not, is uh a bank run.

SPEAKER_01 1:24

Okay.

SPEAKER_02 1:25

And you know why?

SPEAKER_01 1:26

Uh lollipop? No. No, you this is drive-thru bank. Oh, oh, because of the um the the shoot, the the the tubes. The pneumatic tubes. I want to talk about pneumatic tubes. So, so actually, I I'm gonna just jump in real quick. This came up yesterday in a conversation. Um, because I think I told you I was filming at a hospital, and they were talking about at this hospital, um, they they were actually talking about before they got pneumatic tubes, they had to have someone running samples over to the lab, and then they got these tubes to put the samples in and send them to the lab.

SPEAKER_02 2:06

Yeah, hospitals use them for blood work and sometimes for meals and meals, yeah, for lab work. And they it's it's a really great way to send things across like don't get those two things confused. No, no, you can put anything in there. Could you send some ketchup? Oh, wait, that's blood. Like pneumatic tubes are really cool invention, yeah. It's a very not very um, like in terms of the physics, it's not very complicated. Okay, um, it's kind of like drinking through a straw, you know. It's yeah, it uses air pressure. Sometimes they're blowing systems where they blow stuff through a chute, sometimes they're vacuum systems where they suck stuff through the chute, but it's based on Newton's second law, which is says that more force equals more acceleration. Uh and it's just a and there's also a series of valves and switches that make it slow down and turn and go in different directions. And pneumatic tubes were used to be a really big thing. They used to be a lot of places, and it didn't stop because they didn't work or because the technology got any better, it stopped because we don't need physical stuff anymore.

SPEAKER_01 3:17

Yeah, yeah. You don't need a you don't need a bank receipt, um, a physical bank receipt, or even physical money. So they did, you know, you you mentioned why why you like to do bank runs, and I said lollipops. They did sometimes put a lollipop in the in the pneumatic tube and send it back if there were kids. They would sometimes put a dog treat in it and send that back if you had a dog in the car. You know, this is this is like the that is some really personal banking. I like that. Oh, yeah, yeah, yeah.

SPEAKER_02 3:45

Now, it might surprise you to learn that in the 1800s, Paris, the city of Paris, had a full pneumatic male network going on throughout the city. Wait, not female? Oh my gosh. Really? Listen to what I'm saying, man. The male, like the post. The post.

SPEAKER_01 4:05

Okay, okay, okay.

SPEAKER_02 4:06

You could send a message anywhere in Paris to another place in under an hour.

SPEAKER_01 4:13

Wait, wait, wait.

SPEAKER_02 4:14

They had it like not just in one building, but no, it was the whole city was a network of pneumatic tubes in Paris. And that was like that in the 1800s, and it ran like that for a hundred years until 1984.

SPEAKER_01 4:26

Well, they didn't even have black, they didn't even have plastic back then. So, what were the what were the containers made of? Like why do you need plastic? It's just sheep sheep bladders? You could have metal. I mean metal. I mean, imagine that that came out too fast.

SPEAKER_02 4:40

That could be dangerous. No, but that's the whole thing about these systems is that they would speed up and slow down as as needed. I mean, they were very sophisticated. Paris had the the big one, but like in even in New York, they had tubes that connected all the post offices to each other. So you could um you could send something from one post office in Brooklyn to another post office in Queen by a series of these pneumatic tubes that would run under the city.

SPEAKER_01 5:06

Like like the inner like the early days of the internet, right? A series of series of tubes. Right. Yeah, tubes, right? Who was it that said that was Al Gore.

SPEAKER_02 5:15

Yeah, I think it was Al Gore. So he was the one that invented the internet.

SPEAKER_01 5:18

Oh, yeah. It was a politician.

SPEAKER_02 5:21

Yeah, it was a series of tubes.

SPEAKER_01 5:24

So um I I've got to ask, when you say from post office to post office or throughout the city of Paris, are we talking like uh meters slash yards or are we talking miles slash kilometers? Miles. So you could send you could send these things miles away in a pneumatic.

SPEAKER_02 5:42

Yeah, they would probably go, they would probably go from one place and then somebody would repack it and put it to another place. So it might be that you're sending it a quarter mile. Like a tube operator 50 times. Yeah, if it had to go 25 miles or so. Maybe you're sending it and it keeps getting relayed. I'm not sure that was ever like a hundred miles.

SPEAKER_01 6:02

So I wonder if that was a job, like somebody who uh a two tube relay relayer. That wouldn't be a bad job. Like catch it, take one out and put it into the other one. Here's where's it going? Oh, yeah, I see. Okay, all right.

SPEAKER_02 6:13

Yeah, department stores used to send cash from the cash registers, they put it in pneumatic tube and send it like to a central office, like in New York.

SPEAKER_01 6:22

Yeah, yeah.

SPEAKER_02 6:22

Probably casinos might have done that. Sure, sure, within the building, maybe. Yeah, but yeah, you know, tech killed it, but not like a better tech, just different tech that made everything digital. Like telephones killed it for one. I mean, I'm I'm talking about these pneumatic tubes in Paris, like being before telephones, even. If you want to send a message to somebody, you just drop it in a pneumatic tube and send it. That's before the phone. And now I can pick up the phone and talk to you. I don't really need to send a note to you, but that's well no, we we've gone back to notes with tech seems futuristic, yeah. I know. But um, email, obviously, and the maintenance, quite frankly, killed it. I mean, if you get a stuck tube, you gotta have somebody go down in the right tunnels and a tube jockey.

SPEAKER_01 7:13

It's kind of like kind of like or one of those pin pin uh pin boys from the from the bowling alley had to climb in there, or like a rotor rooter, or they probably had those like snakes like they use for pipes, like uh plumbing snakes, you know.

SPEAKER_02 7:27

Because obviously, if somebody's something stuck, well the air's not gonna flow, you're not gonna send a person down there, right? Right. Um, but like you said, hospitals still still use them, and some banks I think still have them, although you don't see them. If you look for them, you're not gonna see a lot of them. Yeah. Um, you know, it's similar, the technology is similar to how the blood pressure actually works in your body that the okay heart creates pressure by contracting, and then the blood cells flow from the high pressure of the arteries into the low pressure of veins, just like the pneumatic capsules would move from these compressed air zones into the vacuum zones. Yeah, it's very similar technology to like how your body works.

SPEAKER_01 8:11

I wonder if they called the had different names for one that went away and one that came towards or a pusher or I always remember artery by away. Arteries go away from the heart, veins come towards. Well, um so imagine how cool it would be to have one of those in your house. To send it where to like from the upstairs to the downstairs. Yeah, yeah, yeah, yeah. Um, you know, you just like send a little um like like dinner, you know, here comes dinner. I mean, it kind of reminds me of like a Wallace and Gromit kind of situation. Have you ever seen those shows? Uh where or have you ever been to New York City to BH Photo? Are you familiar with BH Photo? It's a it's probably the most famous camera store in the world. It's it's huge, it's it's it takes up like four blocks of New York City. They have conveyor belts. So when you buy something, you you you just take a little tag and then you go to the front and then you pay for it, and then it shows up on a conveyor belt. And that conveyor belt system, I mean, like I said, it's four blocks, but it's probably because you can only fit small things in pneumatic tubes. There's probably a size limitation for those. Do you remember the restaurant called in Houston called Two Pesos?

SPEAKER_02 9:22

It was like a knockoff of Taco Cabana. Okay. And um I think your Taco Cabana buildings were like blue or pink, but they're pink, and then two pesos were blue.

SPEAKER_01 9:33

Okay.

SPEAKER_02 9:34

But um, they had the double, sometimes a triple drive-thru, and they would use conveyor belts, and that was so cool to get oh, yeah, yeah, yeah. You could see it, it was see-through, and you could see the food go up and then over the other cars and then down to you.

SPEAKER_01 9:48

But we have a chick-or-that's kind of like that a Chick-fil-A with like a multi-lane drive-thru that has conveyor belts.

SPEAKER_02 9:55

Oh, nice. Well, in 2013, somebody came up with the idea of hyperloop, and this somebody was Elon Musk came up with the idea. Now he didn't do it, put any money into it, right? He came up with the idea that oh, what if you put people in these things and cars, right? And much like we talked about a couple weeks ago, the segue kind of oversold the idea of the hyperloop. Um, the original pitch was that it's faster than flying, and you could go basically door to door and you could go LA to San Francisco in 30 minutes. That was the big that was gonna be the first hyperloop was gonna be basically giant pneumatic tube where you would load people in like a train, and then using the same technology uh with vacuums, you shoot somebody up to San Francisco from LA in 30 minutes. You could go Abu Dhabi to Dubai, and actually there were investors in the Middle East that were gonna do Abu Dhabi to Dubai in 12 minutes. Wow, New York, and then somebody said, Well, if and this is where Musk kind of got off of it, but then there were other people that took that and said, Wow, if we could do that, then we could build one in under the ocean floor, and we could go New York to London in an hour. Yeah, yeah. Um, there was a Texas version that was Houston to Dallas in 20 minutes, Dallas to Austin in 20 minutes, Austin to Houston in 15 minutes. How cool would that be? That did by the end of this podcast I could get to see you and get to your house in 15, 15 minutes.

SPEAKER_01 11:33

Well, no, there's that last mile. Remember, you you'd have to bring a segue. You gotta have a segue on the uh yeah.

SPEAKER_02 11:39

But you know, this involves though getting in a tube like at the bank and then shooting yourself like you know 600 miles an hour.

SPEAKER_01 11:47

It's much bigger than a bank tube. You'd have to really be a contortionist to get in a bank tube.

SPEAKER_02 11:52

Right. It didn't involve, it's not like honey, I shrunk the kids where they would the first technology is freaking you.

SPEAKER_01 11:58

Well, no, you know what the first technology is, and and Musk sort of and um sort of addressed this the hole. Right. So he's got the boring company to to to build these uh to drill these.

SPEAKER_02 12:12

I actually I actually got those mixed up. I thought that he originally started the boring company for the purpose of Hyperloop, but it turns out that's not the case. Um, Hyperloop is a whole separate thing that involves building tunnels for the purpose of pneumatic tubes. And Richard Branson, the CEO of the Virgin Group, actually started this and he actually had the Virgin Hyperloop company, and they had put some money into it. Um, they actually had a test, a human test ride in 2020. There was actually a human test ride.

SPEAKER_01 12:45

I feel like that was on the news.

SPEAKER_02 12:46

Like no, they didn't go 600 miles an hour, it went about 107 miles an hour, which is not even faster than like a uh one of those um high-speed trains. Right. And that's very underwhelming. And um, so they've built test tracks, um, but you know, this is a really this is one of those deals where the technology isn't the problem. It the problem is building it to scale, the problem is the maintenance involved, the problem is the safety. I mean, having emergency exits every you'd have to have emergency exits like every what 100 meters?

SPEAKER_01 13:24

Yeah, ideally.

SPEAKER_02 13:26

People getting stuck.

SPEAKER_01 13:27

Fire suppression. Oh my god. But but you know, you know, there are there are these tunnels that exist. So uh 2017, we went to Norway and visited and drove through some tunnels that were I don't know, 15 kilometers long underground, like bored into the side of these mountains. And so I wonder if you could retrofit those tunnels, which already have a lot of that infrastructure, with with some sort of pneumatic, you know, with some sort of system that pushes maybe.

SPEAKER_02 13:58

Although, you know, if you have a thing like that for roads, um, you know, if if it there's a leakage or something, it they just shut it down the road and then fix it.

SPEAKER_01 14:13

Yeah.

SPEAKER_02 14:14

Uh, if you've got people trapped in a you know tube, that's the a leaking is a whole different animal, right?

SPEAKER_01 14:21

Yeah, the bigger deal.

SPEAKER_02 14:23

Yeah, so and they're hard to slow down too. It's hard that you have to have a lot of technology to slow down a tube that's going 600 miles an hour involves a lot of suction, a lot of those the the blowing and the sucking that's it's it's it requires a lot of uh uh resources there. They have to be perfectly sealed. Yeah, um, and then not to mention you were talking about mountains, but things about things like earthquakes and thermal expansion. Yeah. Um going 600 miles an hour, that stuff is a there's no there's no room for air. No room for air. And you know it would happen, right? Yeah, especially if you're talking about digging a tunnel across the Atlantic Ocean. I mean, I mean, just digging a tunnel like where you drive in the Detroit River, like when you go to Detroit to Windsor, yeah, it's probably a half a mile. And um, that's a big deal. I can't imagine digging something across or the channel, right? The the train that goes from New York to London to Paris. I mean, I can't imagine um, you know, that took over a decade to build, I think, and that's just across the English Channel. Um, so really it's not the technology that's the problem, it's just the maintenance and the building it to scale and how much the massiveness of it. And by the time we instead of focusing on that, we'd probably be better off just focusing on like high-speed rail. Or maybe you build those pneumatic systems, but you only put cargo in them. Like maybe FedEx could, you know, pony up a billion dollars and and put together these these, you know, this Texas triangle, but only with cargo, and you wouldn't have people's lives, or maybe like a driver, you know, um, but not for transportation, not to move instead of airplanes. It just seems like it's one of those things that we even if we get the technology, it'll probably never happen.

SPEAKER_01 16:11

Yeah, I mean, there's a lot of lobbying against it, I'm sure. You know, a lot of people that are like, you know, hey, I like things the way they are, we make money the way things are.

SPEAKER_02 16:19

And even if you finally do like build it, convincing people to get into a tube and go 600 miles an hour. I mean, think of how long it took. I mean, air travel is like 99.99999% safe, and there's still people that are would never get in an airplane, right?

SPEAKER_01 16:38

Yeah, yeah.

SPEAKER_02 16:39

And this stuff is not gonna be nice, we're not gonna at first be that safe.

SPEAKER_01 16:44

Well, aircraft airplane air travel wasn't that safe at first either. Exactly. Exactly.

SPEAKER_02 16:50

Um, I bet it would cost more to do this than to actually send people into space.

SPEAKER_01 16:58

You know, I I was thinking about um this a moment ago as you were talking about these tunnels. One of the things that they've talked about with the Artemis missions is on the moon um having these bases be in existing um tunnels that are under the moon's surface to help protect from radiation and protect from like micro and and larger impacts that happen with uh you know space junk and meteors and stuff like that.

SPEAKER_02 17:25

So there's already tunnels yeah, yeah.

SPEAKER_01 17:27

There are there are tunnels under that that have happened naturally, you know. I think that's just part of the rock formation. But then you then you get this as a way to move around the moon. You've got lower gravity, um, you've got a need for it, you've already got tunnels that exist, and you can build the cement or whatever you use to make the frame out of the the the you know they're talking about being able to build use the moon's moon dust and the moon rocks and stuff like that to be able to make um make oxygen. You did it, man. You cracked the code.

SPEAKER_02 18:00

Callness.

SPEAKER_01 18:01

There's a problem. What what pushes the what pushes the um the pneumatic part of it? It's air. There's there's no air, there's no there's no gas to push. Um, you know what I mean? It's a it's a vacuum. So it is it is a vacuum tube, not a pneumatic tube. So you got the vacuum part sealed. So I guess maybe if you put air in one side, it would get sucked through it. You know, maybe you just need a burst, like a small burst would be more powerful. I don't know. I'm gonna call NASA. I'm gonna get I'm gonna get right after this call. Call their customer service line after a place for crack quacks like you. Well, you know, you you you live close to NASA. Why don't you go down and and talk to them in person for me? Yeah, take somebody to lunch.

SPEAKER_02 18:41

I just knew the right person to to talk to. I could take somebody to lunch. Um so, like I said, the the um these tracks have been built. Hyperloop one was the big company that um was what that had all this stuff going that built the test tracks that did the test ride, they shut down in 2023. So currently nobody's working on this. Man, um it's a great place to rebrand this is the Dirtnap City Hyperloop.

SPEAKER_01 19:08

Uh oh, and if somehow we could get segues in these tunnels, in the existing tunnels, right? Uh-huh. Maybe maybe you get pushed along on a segue, and and and then that way you can just pop right out. There's like little ramps that you pop out at different places that plays our podcast on the in the speakers.

SPEAKER_00 19:26

Right.

SPEAKER_01 19:27

Um yeah, yeah, I'm liking this. I like I like the cross branding.

SPEAKER_02 19:32

Yeah, and then of course, the big the punchline is that every uh every hyperloop at the end, it's a dead end.

SPEAKER_00 19:46

There's a tube in the wall for a check and a grin. A little paper rocket spinning fast within. You drop it in a sleeve and it disappears. Then whoa, there it goes through the hidden gears. Worrying in the wall, swishing down the line. Tiny little miracle working all the time. Worry, worrying, worrying, swishing through the town. Two pop, two pop, send it up, send it down. Simple and sleep, and so how it slides. Worry, squishing, right before your eyes. In a hospital hall where the day runs thin. Sample a chart, get it moving again from desk to desk with a soft little scoop of blood test and note in a zooming loop. Worry in the wall, switching fast in light, saving all those minutes when the minutes buy. Worry, worrying, worrying. Switching to the town, too pop, to pop, send it up, send it down, simple and slick, and done how it flies. Switching right before your eyes. Now here comes the wild card, stretching out ahead. Silver strat idea for the roads we dread. Cross the whole damn country in a flash and a hum. To do the plan and the future come, worrying, worrying. Squishing through the town, to pop, to pop, send it up, send it down, simple and slide, and some how it fly. Worry, squishing right before your eyes. Simple little wonder making a giant mark.