To Keep Or Not To Keep? The Case Of The Kyoto Imperial Palace

I sighted this Vectron at Karlsruhe: a Dual Mode, which can move either with its Diesel engine or getting its energy from the overhead wires (German 15 kV AC only for now). However, it only delivers a third of the power of a standard all-electric Vectron, and is therefore not designed for main line hauling, and is expected to be more at home near sorting yards. Deutsche Bahn have also bought some of these as ICE rescue locomotives, serving when a train breaks down.

For Vectron!

Produced since 2010 by Siemens, the Vectron is a modular locomotive platform with various engine options - AC electric, quad-voltage for use across Europe, "last-mile Diesel" option for parking, Diesel motors, dual mode/hybrid... It hauls both freight and passenger trains. But the main reason I've wanted to mention the Vectron is...

this Mitchell and Webb sketch!

This is from series 3 of That Mitchell and Webb Look, which was aired in 2009. The Siemens Vectron was officially launched in 2010, so it's fair to say that the name appearing in both is a coincidence. However, when I see a Vectron, it reminds me of this sketch, so it's harder for me to take this train seriously!

But it is serious business, as it is one of the most common locos in continental Europe. Only Iberia (due to using a different gauge) and France (because if it ain't Alstom, they'll oust 'em) don't see much of them. The examples shown here are from Germany, Switzerland and Slovakia, and were all pictured in the same area of Germany. The quad-voltage version in particular allows companies to carry freight all over Europe, they're virtually borderless.

Yet here I am, still snickering at the name, by Vectron's beard!

It's time to go back to Kashihara, and let's start by meeting the local animals!

I'm getting real "fancy pants" vibes from the cat! But to be fair, it is a darn good looking cat.

That is all until I think of something more intricate to talk about.

Grand Geroldseck castle - only a cat of different coat

Close to impressive Haut-Barr castle, a one-hour hike from Saverne, sit two more ruins. All of these castles were built around the same time, late 10th to early 11th century, but despite being so close, they weren't owned by the same people.

While Haut-Barr was under the control of the Bishop of Strasbourg, the two Geroldseck castles, the Petit and the Grand, were built by the Geroldseck family, in charge of protecting the lands of the Abbey of Marmoutier. At the time, Alsace was part of the Holy Roman Empire and divided into many largely independent pieces, so these castles facing each other were on a border of sorts. However, the male Geroldseck line went extinct at the end of the 12th century, and the land was co-owned by so many people that no-one was maintaining the castle. The last stand came in 1471, when a group of disgruntled knights used it as their base. The Imperial bailiff laid siege, won and the castle was left as a ruin after that.

While Haut-Barr castle gets a lot of visitors, owing to the possibility of driving there, the Grand Geroldseck is worth the extra walk and brief climb from its neighbour. As well as the dungeon, lots of walls and rooms are still present, making it an interesting place to explore. The remaining walls continue to receive restoration work - there seem to be a few differences between my first visit with @teamroquette and my second this summer, for example, I don't remember seeing the little garden a few years ago.

All that's left to say is: "OI YOU!... YES, YOU! Have a good time."

I'm a bit low on inspiration and time today (work starting to pile up), so here's a train in the snow from the recent trip to Mulhouse and Thann. The train itself is a bi-mode Regiolis B84500 set, waiting at Mulhouse as the Sun sets.

Sangaku Saturday/Sunday is taking a week off.

Koishikawa Kôrakuen in the summer

This is my favourite park in the city and I've now seen it in three of four seasons, including exactly one year ago. As August in Tokyo goes, it was very muggy and overcast, and as soon as I touched the ticket, it started raining. As I hadn't entered, the person at the ticket office offered a refund, but this was my last day in Japan so if it was going to be a wet visit, so be it.

I did shelter for a bit as the rain was rather heavy, and it proved to be a shower, so it was mostly dry during the walk through the park. Well, I say "dry", but the air was horrifically humid, I was getting just as wet when it was raining than when it wasn't! And when the Sun peeked out, wow did it burn!

Through all of this, this one heron seemed to be chilling in the middle of the main pond. Heron? Hero, more like!

After the tour, I went to the Kantoku-tei tea house for some respite, a katsu meal, some tea... and a change of shirt!

Everything is ready for Tuesday! How this particular configuration works, as well as the one below, will be covered - we can talk about it on here too afterwards if anyone's interested.

C'est avec grand plaisir que je présenterai le mardi 16 avril à la Maison Universitaire France-Japon de Strasbourg une conférence sur la géométrie pendant la période d'Edo, avec en support le sangaku de Kashihara. Entre grande Histoire et petits calculs. Lien vers les détails 4月16日(火)、ストラスブール市の日仏大学会館に江戸時代の算額についてコンファレンスをします。楽しみにしています！ Looking forward to giving a conference on Edo-period geometry on 16 April at Strasbourg's French-Japanese Institute. Expect a few posts about Kashihara around then. Has it really been 6 years?...

Summer highlight reel: Île de la Table Ronde

To the South of Lyon, the "Island of the Round Table" in the middle of the Rhône offers a fantastic escape from the city. While the East side is exposed to a lot of noise from motorway traffic, the inside and West shore are gorgeous, and the southernmost end is a nature preserve.

The river flows by at a steady pace, making it a good spot for a reaction ferry similar to the ones in Basel. Fair play to the locals, they thought that too!

Bridges now do the job - though the suspension bridge from Vernaison isn't doing too well. Built in 1959, it needs replacing and until then, traffic is limited on it so as not to overload it. This hasn't been helped by the North side of the island being an industrial estate.

In the centre of the island, one finds a ruined farm, the Ferme aux Loups. One thing @teamroquette likes to do is geocaching, and so we looked for some, but the most elusive geocache of all was the namesake of the island. There are pictures of a round table associated with the island on Google Maps, but we missed it. That said, one Google review also mentions that they couldn't find it, so who knows.

We did find these interesting and somewhat imposing water level meters though. Lay on them to measure yourself... and get the wrong answer!

More views of Schonach

A quick post today as I don't have much time... So here are some views around the ski jumping hill and cross-country skiing venue for this weekend's Schwarzwaldpokal.

Sangaku Sunday #7

We're back with a new problem from Miminashi-yamaguchi-jinja! This is going to be more ambitious than the first one, though it won't be much harder from a geometry standpoint - the main tool will still be Pythagoras's theorem. But we really need to set the stage for this one.

Consider an isosceles triangle, with two circles whose diameters are on the height from the apex, tangent to each other, and so that the top circle passes through the apex and the bottom circle is tangent to the base. We seek to draw one more circle on either side, which is tangent to the first two, and tangent to two sides of the triangle.

Details and first questions below the cut.

The triangle is given: it is an isosceles triangle SNN'. For the sake of simplicity, let's shrink or blow up the figure so that the height SO is equal to 1 (for a configuration with height h, we will just need to multiply all the lengths by h). The length of the base NN' is therefore the fixed parameter of the problem, and, as the figure is symmetric with respect to SO, we only need to set the length ON as our parameter: set ON = b. Hence, we are working in the right triangle SON.

The problem involves finding the three circles that fit the configuration in SON. Let these circles have respective centres A, B and C, and respective radii p, q and r. The radii are the unknowns of our problem, and we need to find three independent relations between them to solve. From the sketch, it looks like there should be only one solution.

The first relation is obvious: 2*(p+q) = 1, as the diameters of the first two circles form the height SO. This is also very easy to solve: if we have p, then q = 1/2 - p.

A second relation must start to involve r. For this, project the centre of the third circle onto SO and ON, calling these projections P and Q respectively. Now we get to two questions for you to munch on.

1: Prove that

2: Get the lengths AC and PA. Deduce another expression for PC, and prove that

With that, we just need another equation to find p, and we'll be done.