Comment by wolverine876 | Hacker News Reader

Comment by wolverine876 | Hacker News Reader

From the Financial Times article [0] cited in the OP:

Mexico’s government is bullish about prospects for the rail crossing, which will offer proximity to the US and a transit time of 6.5 hours excluding loading time — less than the eight to 10 hours it takes on the 80km canal.

Much more than transit time, I'm interested in throughput. How long does it take to move a full container ship's contents from one end to the other? How long does it take just to unload and load?

Also, regarding loading/unloading: When I think of a train, I imagine it being loaded/unloaded in semi-serial - first the front cars, then the next set of cars, as the train moves segment-by-segment past the ship. Essentially you are transforming a massive pile of containers onto a long string of containers. Is that correct? Is there any solution to speed it up? I suppose they could lay several train tracks in parallel alongside the ship and use extra train engines to pull up groups of rail cars, and then reconnect them into one long train as the train pulls out. How long is a train carrying a full container ship's capacity?

Cost seems the other essential question: Sea transport costs a fraction of rail transport, generally, but I expect that canal transport is far more expensive than open sea transport.

[0] https://www.ft.com/content/bbe8e851-e9f2-4ed1-a4a7-051a670b4...

Apparently it takes about 3 days to unload a "full size" container ship.

So this rail isn't going to be tremendously useful unless they connect it directly to the USA.

As for loading the trains, they already do it in parallel; look at an arial photo of a stockyard. For this specific use, you could parallelize it even more I suspect.

Yea, I don't really get why the 6.5 hours is particularly pertinent. The unloading time (and expense) will dominate, and any other railroads connecting a Pacific port to an Atlantic port in the Americas that are less than ~2 days transit time will be competitors.

Why does connecting directly to the US help? If you're in one ocean and just want to access the US, can't you just steam direct to a US port?

By the jones act ships cannot go US port to US port. so all ships plan to unload once. this can work aroud that by letting a ship unload some in Seattle and then send San Diego from Mexico via train (or whatever variation makes sense)

I mean ok but why not just unload at any mexican or canadian port with a rail connection to US? Why go all the way down to bottom of mexico?

By ship is still by far the cheapest way of transporting cargo, and the proposed route would involve the shortest land distances.

More importantly the Sierra Madre ranges are large geographic barriers throughout most of Mexico but are relatively flat in the area of the Chivela pass, where this rail line is.

My comment was discussing using the rail for access to the US, not for getting from one ocean to another.

Most of the US lives on the East Coast so at some point those mountains have to be crossed.

The elevation of the plateau in between the Sierra Madres is no joke; Mexico City is at 7349 ft elevation.

They can. However if the goal is the center of the US ports in Mexico may be closer (remember mountains cause are expensive to cross and so a straight line on a map may not be the best route). I'm not in logistics so I can't tell you all the considerations used to decide if they should stop in any particular port or not.

Right now the main thing controlling where the ships land is where they have ports that can receive their massive tonnage; places like Long Beach (16,618 TEU) or Houston (3,974 TEU). It's quite arguable that additional ports need to be built so that the ships can disperse cargo closer (or even farther, but more efficiently) to where it is going.

That's not quite right. Boats can't pick up cargos in one US port and move them to another. They can drop in multiple places but it is usually uneconomic.

If a boat that would go through the locks could unload in Mexico and send it to its final destination it might be worth it, but unlikely (time wise).

The whole thing comes into its own if Panama is overloaded and the other option is taking around the South America).

> How long is a train carrying a full container ship's capacity?

According to Wikipedia[1], "Container ship capacity is measured in twenty-foot equivalent units (TEU)."

And container ship size categories are (conveniently!) based on what can fit through the Panama Canal. Neopanamax ships are the category that can fit through in the canal's new (upgraded) configuration, and those can hold 10,000 to 14,500 TEU.

For round numbers I'll use 10,000 TEU. That means if you laid all the containers end to end, they would stretch out 200,000 feet, which is about 38 miles or 61 km.

Trains can stack containers two high[2], so divide that by two, and a train has to be at least 19 miles or 30 km. But really somewhat longer since one train car's containers don't butt up directly against the next car's containers.

So presumably they would need multiple trains for one ship's cargo.

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[1] https://en.wikipedia.org/wiki/Container_ship

[2] https://en.wikipedia.org/wiki/Double-stack_rail_transport

Afaik, some container ships are made much larger than what will fit through the Panama Canal. If you are shipping from China to anywhere in the Indo-Pacific, you don't need to worry about canals.

> How long does it take just to unload and load?

If it is more than 8-10 hours, you start getting overlapped I/O.

As to parallelization, I wonder how much of the route is a single track. Parallel tracks could allow coming and going without interference. (then there are siding and crossover tracks, etc)

I also wonder - do you have to unload EVERYTHING? maybe just the express cargo, while the rest of the ship waits.

Or you could combine ship cargo and one ship could make the long trip, while others return back across the pacific.

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