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Comment by 131hn | Hacker News Reader

Am i reading right ? 17b € for a 57km tunnel (on an existing railway, only to flatter trajectory a little) just to save a little time ? That seems expensive..

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"Just a little" reduction in grade can mean quite a lot. The grade on a typical staircase is about 60%--for every meter of horizontal distance, the staircase rises 60 cm. In terms of hiking, one trail I went downhill had a persistent 30% grade for 1.5km or so, very much to the complaint of my knees. A persistent 10% grade would usually be considered quite strenuous for hiking.

For roads, the maximum permissible grade is lower. The steepest road in the world is about 37% grade; the exit on a highway signed "Truckers: DO NOT USE" was 13% grade. In general, anything above about 5% grade requires excessive grade warning signs.

Railroads have even stricter grade tolerances. The original B&O used "inclined planes" (effectively stationary locomotives providing extra pulling power) to navigate the tortuous 5% grade in Mt. Airy. This was quickly replaced with a 1.5% grade loop and eventually a tunnel (.8% grade). In general, freight railroads like the max grade to be around .5-1%, although mountainous terrain is usually not so forgiving (most of the major passes in the Rocky Mountains run about ~2-2.5% grade). The steeper grades require either extra locomotives to be put on the trains or the weight of the trains to be drastically reduced.

I've seen trucks (tractor-trailers) with flames coming from the brakes on 6% grades downhill... and the uphill sides of those the trucks are in low gear at high RPM doing 15-20mph MAX, running at 3-4x the rpm they'd run doing 75 on the highway... people underestimate grade and the effect it has on heavy vehicles

The maximum commercially viable (due to weight restriction) grade for freight railroads is 2.2% ...

If you want some hard numbers on why high grade is so problematic:

When you're pulling something along a road or a railtrack on level ground, the primary force you need to overcome is rolling friction, which is proportional to µ×N, where µ is in the range of 0.001 (rail) to 0.01 (road) and N is the normal force against the surface. For a 10 kN car (that's about 1000 kilos), this means that you need a force of about 10 N for a railcar. When you go up an incline, the rolling friction decreases according to the cosine of the angle, but now you need to overcome gravity--and this amount goes up by the sine of the angle. A measly 2% grade requires pulling a force of about 210 N, a factor of 21×.

Basically, grade really kills because you actually have to counteract gravity as opposed to friction.

First, thanks! I genuinely appreciate that knowledge, I'd have never looked it up on my own..

Second... why's gravity gotta be such a dick? :)

The maximum commercially viable (due to weight restriction) grade for freight railroads is 2.2% ...

A 2.2% grade seems insignificant to the average person, but to a freight train it is no laughing matter. Here's a serious derailment that happened in California: https://en.wikipedia.org/wiki/San_Bernardino_train_disaster#...

At that grade it's not sufficient to use brakes in the individual rail cars, it's also necessary to use dynamic braking by turning electric traction motors into generators, then dissipating energy in giant resistive grids.

The old rail route through the Gotthardt pass runs in a set of vertical spirals to achieve the vertical elevation.

This megalink shows, I hope, a Google Maps 3D rendering of the pass and the rail route:

https://www.google.co.uk/maps/dir/Schwyz,+Switzerland/Locarn...

Note that the big loops are inside the mountain.

We have some absurdly long (3-4.2km) freight trains in Canada, and they go through systems like this all the time. You can see the front of the train at the top of the mountain while the bottom is still going in!

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

https://en.wikipedia.org/wiki/Spiral_(railway)

The trajectory is flatter with the new tunnel and freight trains can be longer and carry more weight. This is one of the elements in trying to shift more freight from the street to the trains (which is one of the two points of the Alpen-Initiative, a popular initiative from 1994 to protect the Alpine Environment).

Except that, according to the article, it doesn't really shift traffic, but creates more of it.

Well, that is not jet clear. Either are not bad situations and don't make the investment bad.

I'm not sure whether the environment thinks the same about that. (As long as only train traffic increases, it should be fine, as that uses electricity from water power in Switzerland. Not so for car traffic, which should ideally decrease unless it becomes electric.)

Yes, that's true. But it came into being as part of the actions taken to satisfy the initiative.

Time is money. :)

Also, this tunnel probably increases transportation capacity as well.

Consider that above the tunnel there are the Alps.

What else should a society, that has almost everything, invest in? It's not like they are neglecting anything for it, they literally sit on gold.

By that logic you could just tax less. That was definitely not the reason this was built.

I was referring to society, not the Swiss state. I don't think that they could have spend that money better individually. The tunnel will be there for a while, so you have to write off these billions over decades. After you divide the remaining by a few million Swiss people, there isn't much money left.

Decades? Why not centuries!

Heavy investment in transport seems quite natural in a country where many settlements would be virtually unreachable without impressive projects. Smaller projects, very much unlike a Basistunnel, but still magnitudes more expensive than just paving over a dirt road. If you have seen the love, respect and money the Swiss allocate to maintain their awesome Postbus and conventional rail networks, a few billion to solve transit with tunnels do not seem terribly surprising anymore.

that is Switzerland :D

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