Comment by acd | Hacker News Reader

Comment by acd | Hacker News Reader

I hope Sweden and Germany can make a common DIN Deutche industri normen standard for charging electric vehicles on roads. There would be an added benefit if we could build rail tracks among the electric guidance line. Rail tracks to lower the rolling resistance, metal on metal vs rubber on asphalt. We would then have a hybrid car rail track which should make it easy for autonomous driving. The aim would to bring down the total co2 emissions of transportation. Building both in ground and above ground electrification of cars would be the best system as then cars can charge during good weather conditions and trucks can always charge even during winter time. A system with electric guidance in the ground is a bit vulnerable to snow during winter times.

Here is another more rail like track which can be used by trucks but not by cars. https://www.scania.com/group/en/worlds-first-electric-road-o...

Rolling resistance coefficient c of rail c=0.001, dirty tram rails c=0.005, car c=0.02. Ie rails resistance is at least 25 times lower than rubber on asphalt 0.005/0.02. https://en.wikipedia.org/wiki/Rolling_resistance https://www.engineeringtoolbox.com/rolling-friction-resistan...

Let's just only have train tracks? We can still have electric trucks for the last mile, but then they won't need electrified roads.

Long-distance goods transport with trucks is such a ridiculous concept, it's really time we just face it: it only ever made sense because the state funds the roads and road repair from general taxation, we have ridiculous subsidies for the fossil fuels that make it run and trains had the misfortune to be invented such a long time ago that the government has suffocated the industry.

Rolling resistance is somewhat of a rounding error, by the way. The big killer is aerodynamics: the power needed to push air out of the way increases quadratically with speed. But there is a cheat code: if you make the vehicle longer or add something to the back, it can ride in the slipstream. Only you can't make trucks very long at all because they need to work on public roads. Trains on the other hand can be made ridiculously long, saving massively on energy - multiple miles of wagons if you so wish.

Moving goods from the train to the truck is not a negligible cost. Also, you have to move lots of things in batch with the train, which makes product and supply chains unless nimble. Perishable agriculture products, for one thing, benefit greatly from truck transport.

A nimble supply chain, or "just in time" as they call it, is a hack large companies use to shift quantities from one column of their quarterly reports to another that the stock market looks more favourably upon. Analysts can't very well quantify the risk of a JIT supply chain but they know cash flow over finished goods.

That isn't true. It means you need less storage space, and you need less capital tied up in parts you aren't using. It also means your cabbages don't rot.

> Moving goods from the train to the truck is not a negligible cost.

Really? I was under the impression that this was one of the primary benefits of standard shipping containers.

That goods transfer costs would be negligible?

Between shipping modes, yes. Hence the name "Intermodal Container".

https://en.wikipedia.org/wiki/Intermodal_container

Yes. Unloading stuff from a container is not a negligible cost, but transferring the whole thing from a train to a semitruck really should be. It is a very large part of their purpose.

Tracks are a superior design in theory but fail to be flexible enough to work in varying weather conditions and complex dynamic routes. It's better to have invisible guidance rails and let vehicles maneuver easier.

> We can still have electric trucks for the last mile

I think you're grossly underestimating how spread out truck destinations are. You would have to have a very extensive rail network to get cargo anywhere near all the destinations where it's currently trucked. And if the rail network doesn't fall within X average distance of every destination, the value proposition of this idea rapidly becomes negative.

At high velocities (> 40 km/h?) the main drag comes from aerodynamics (turbulence, air viscosity…), not rolling resistance.

perhaps with autonomous cars and rails the cars can follow each other very closely so improves aerodynamics too.

indeed

They already trialed that with trucks where several trucks form a convoy, controlled from the first one. Saves ~30% fuel for the following trucks. That could be used flexibly and probably contain 5-6 trucks minimum without disturbing traffic.

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