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Comment by throwaway892238 | Hacker News Reader

Why would you use drones for this when you can build a very small rail network? Drones can't carry very much, and they can have problems in flight that will lead to dropped/damaged goods, not to mention they'll require more energy. A small rail network could transport the same small goods over the same areas with less energy and no potential dropped/damaged goods.

Their aerial route should ideally not go over forested or ecologically sensitive areas, in part to avoid contamination from crashed drones, and in part because drones push birds out of their nesting and feeding grounds, and territorial birds actively fight small drones.

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From the article:

> The Royal Mail is aiming to deploy a fleet of 500 drones to deliver mail to remote areas, starting with small islands like the Shetlands or Orkneys. Britain’s National Health Service is trialing drone delivery for medication, specifically chemotherapy drugs, to cancer patients living on remote islands; one such route would save patients a three to four-hour ferry ride to the mainland and back to pick up their medications.

Couldn't this also be solved with a freezer on the island (+ shipping larger quantities of these drugs regularly via whatever process usually brings parcels onto the islands).

I am not complaining about a drone highway, sounds great. It also sounds like quite an oversized hammer for that specific problem though.

Shetland and Orkney are both made up of lots of islands - many of them inhabited.

Sounds a little dangerous, if you're talking about mailing irreplaceable things (talking more like mementos or cheap collector's pieces, not something you'd actually insure and fedex) - or am I overvaluating a stray bird knocking down a drone over the sea, versus mail simply lost in transit?

Because it’s a lot less work to build out some ADS-B infrastructure and make some airspace rules than it is to build a railway.

I don’t know for sure, but I suspect that if they just have the drones fly at 2000’ AGL that would significantly reduce the impact on birds.

Fun story: why is the current rail system buckling and warping in the heat? Because someone in their wisdom decided to weld the expansion plates to stop trains going clickety-clack in residential areas. The noise is why you won't see much support for rail networks. I say bring on the rail infrastructure, it is the greenest method of moving freight.

> it is the greenest method of moving freight.

Water transport, where available, is far greener than trains for moving freight.

Anything you can cite here? I think of water as extremely fantasically high drag. I know that scales inversely down proportional to size, but I still think of rail as the ultra-efficient best option. Would love to read more detailed review/analysis.

https://truecostblog.com/2010/05/27/fuel-efficiency-modes-of....

The TLDR is, on the surface of the earth the slower you're going, the more efficient it tends to be. That even holds for, for example, making trains or cars move slowly: they'll be most efficient at a pretty slow speed. Even planes are most efficient flying 0.0001% above stall speed, the slowest they can possibly go.

Most energy in transport goes into moving the atmosphere out of the way.

Planes fly high, but that really only makes them comparable to a car. Surprisingly that also means that for really long-range transports even rockets aren't as inefficient as you'd initially think.

This thread made me curious, so I looked up engine sizes between trains and boats.

A transport ship[1] can carry 9500 TEU with 53,000hp. That’s 190,000 feet of containers, or 36 miles.

A train can be 1.5 miles with 4000hp per engine. (According to Google “facts”.) That’s 24 trains to move the same containers, with at least 96,000hp between them. (And that’s ignoring a 1.5mi train will have more than a single engine.)

That trains use more horsepower to move the same freight suggests that they’re less efficient.

[1] https://en.m.wikipedia.org/wiki/COSCO_Guangzhou

Don't they usually stack containers two high on trains?

If you have old infrastructure with low overhead (old tunnels and bridges for example) you can't run that and you need to use rail yards to assemble/disassemble container stacks. It gets expensive fast.

Hah, fair, I've only lived in the western half of North America, where infrastructure was almost all built after heavy rail lines were laid down.

... obviously then a floating canal train, would beat both of them. The best of both worlds!

My Toyota Sequoia has close to twice the horsepower than my Cessna 182 did, but the Cessna burnt easily twice as much fuel per mile than the Toyota.

The Cessna cruised at 65% power. The Toyota cruises at closer to 10% power, but needs the excess power available when a hill comes along.

I suspect a similar dynamic exists with trains and ships - trains need to have power available to go up a hill, while ships probably cruise at closer to full power.

Thanks. To dogpile on what a bad measure that was, I'd add another example:

A Tesla Plaid S is 1020HP.

Is it less efficient because the engine is oversized? Seemingly the opposite. It's 33kWh/mi compared to the nearby Performance S (with similar 21 inch wheelsizes). If we assessed miles*capacity/hp though, things would look incredibly dire & dark for the Plaid; the worst EV in production perhaps?

In general, engine output capacity doesnt really tell us much.

Doesn’t the need for locks make it incredibly slow?

That would be latency vs. throughput, i.e. good for things that need a steady supply like food, and bad for one-off low-latency things like mail.

I'm pretty sure that I read somewhere there are like 100 freighters that produce as much emissions as all cars on the roads globally.

It's far greener per ton of cargo, not absolutely.

That was talking about sulfur and nitrous oxides, not CO2. And that's because once they're out away from ports, they burn cheap bunker fuel which is ridiculously dirty. This can be easily addressed by switching to other fuels, and some places have already banned bunker fuel since that report.

Clickety-clack is also bad for high speeds but Im not sure how fast are they in the UK.

Up North they're not very fast, the rail network has a lot of tight bends that makes it unsuitable for high speeds, particularly around the coastal areas, this is even after giving up a lot of legacy routes and stations to improve efficiency. We don't do planning very well in the UK. Liverpool city centre is a prime example of poor road planning in particular. Complete spaghetti.

> Complete spaghetti.

Birmingham is the OG of pasta-named roads however.

https://en.m.wikipedia.org/wiki/Spaghetti_junction

Today I learned! Wow!

On the West Coast Main Line, one of two major routes that goes from north to south, trains run at up to 125mph.

I'm fairly certain that reduced noise is just a beneficial side effect and that the original motivation for continuous welded rails was less wear and tear, less required maintenance and better ride quality. It's also a necessary prerequisite for running at higher speeds, because a rail joint can only be subjected to so much forces before it starts failing at an accelerated rate, and dynamic impact forces while transitioning a rail joint naturally increase with speed.

Or even electric trucks (could be self driving eventually) on exisiting roads. Use transit lanes to prioritize sharing and more efficient use of said roads.

It has to be more energy efficient.

I get the drone idea for emergency medical supplies like blood, or even as an ambulance.

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