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Comment by AstralStorm | Hacker News Reader

But do big enough trains exist? As in, is the container ship only 4x bigger than the train?

longest train according to wikipedia is 18.000 feet (3.4 miles). If a 40ft containers needs a 60ft car, and they are double stacked, then you can fit 30022 = 1200 TEU of containers on that train. A single large container vessel has 20.000+ TEU of containers onboard. So nope, trains are a lot smaller than container vessels

Why would we want to reproduce the exact same model? Maybe more, smaller trains would do just fine instead of a single gigantic one.

Also, I'd say trains could be easier to automate, so having several smaller trains instead of a single huge one wouldn't be an issue, as you wouldn't add the cost of personnel.

Trains can also go to different places easier, so you wouldn't have to move container several times.

Is there a hard limit on how long a train can be?

Longest freight trains currently run upwards of 2km. You could make trains longer but various issues crop up such as ability to radio reliably the whole length of the train for telemetry and distributed locomotive control. Also the brake line systems typically used (air actuated) becomes a factor as well as safety (can't see the whole train)

Which country? I'm not a train nut, but 2km seemed middling in the U.S., so I Googled it:

> SMART Union transportation division spokesman John Risch told top rail regulator the Surface Transportation Board (STB) at an October hearing on CSX service problems the average U.S. train is up to 1.5 miles long (2.41 km), but CSX has routinely operated trains two or even three miles long since Harrison took over.

-- https://www.insurancejournal.com/news/national/2017/12/07/47...

And what happens if trains become significantly larger than segments.

Trains cannot occupy a whole track from China to Vienna for themselves, right? You need bypasses, stops, segments, etc.

Edit: typo

Oh wow, had't thought of that, I'm shivering from Factorio PTSD at the idea of handling kilometers long trains !

There's going to be good reasons for why a ridiculously long train isn't worth it when it comes to cost-benefit, but these reasons just seem contrived:

> radio reliably

The cars are physically connected, why couldn't you run repeaters down its length?

Presumably any issue you'd have with sightline radio on a >2km long train now you'd also have with a ~200 meter train halfway through a ~50 meter tunnel.

> the brake line systems typically used (air actuated)

And have N independent break systems with central control. It should be more not less safe, a complete failure of one system could be backed-up by another.

> can't see the whole train

So run CCTV on the same system you're using for the radio repeaters?

Aside: “Trains in Switzerland are not allowed to have 256 axles” - see https://news.ycombinator.com/item?id=21298399

Another issue is at grade road crossings. There are limits as to how long you can close a crossing preventing road traffic from going through. The longer the train the longer the crossing is closed.

I think the vast majority of railroads have at grade road crossings [exceptions might be high speed rail.] Does anyone know?

Safety and the steepness of the track, among other things.

Regular freight trains from China to Europe are a real thing by the way, no need to speculate. Service is running flawless as well.

Yeah they use them for expensive goods that need to move faster than a ship and not as fast as a plane. Things like laptops and computer parts. A lot of industry is moving from the Chinese coast to remote provinces that don't have coastal access.

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