File talk:BSicon utSKRZ-G2o.svg

Road under rail tunnel? Yep, it exists: here, (pt:Linha Amarela (Metropolitano de Lisboa)) -- Tuválkin ✉ 04:03, 5 December 2011 (UTC)

That's just a bridge over a roadway, with a rail line on the lower deck. :A much better example is the Bloor Viaduct in Toronto.
I would be a little more inclined to accept the TTC's Rosedale Valley bridge as a "tunnel over a road" (see here), but it's actually an enclosed structure (for noise prevention) that appears similar to a tunnel from the inside.
Perhaps  (utSKRZ-G2o※ RP4)  would be more accurate? but as it stands now, the icon doesn't make a lot of sense. Useddenim (talk) 06:04, 27 December 2011 (UTC)

See also Talk:BSicon/Icon topology and semantics » "No bridges below surface"— NOT! for more thoughts on underground crossings. Useddenim (talk) 06:06, 27 December 2011 (UTC)

It is not a «a bridge over a roadway, with a rail line on the lower deck». It is a tunnel running under, and parallel to, a regular road (actually one of Lisbon's major avenues) which crosses a tunnel dug under said avenue where a another, lesser, road/street goes. Due to depth of the subway tunnel, built btw about 100 years after the deeper and shorter transversal road tunnel, it intersects the older tunnel not above the vault of its arch but through it and thus passengers riding a subway train will get a glimpse of the lesser street. All this is obvious here.

The Bloor Viaduct is not a much better example, nor better example, nor even an example — of the same thing. I would use this icon to symbolize it, surely, as enclosed track and tunnel do have certain similarities, as you say, and icons should not attempt at such fine distinctions, but my example and usage at pt:Linha Amarela (Metropolitano de Lisboa) refer to an actual tunnel running under a regular road dug through soil and bedrock, not at all «on the lower deck» of some bridge.

You propose  (utSKRZ-G2o※ RP4)  (or better yet  (utSTR※ RP4oRP2) ?), which is fine for track «on the lower deck» of some bridge (I used it myself at pt:Linha do Sul for this+this), but not for the situation at hand. You claim that  (utSKRZ-G2o) «doesn't make a lot of sense» (after suggesting that an overlay including it «would be more accurate»…?), but it is exactly what I intend to convey here and it matches perfectly the approach used in this diagram and its kin:

In the Lisbon metro detailed line diagrams we are not marking trivial surface features, such as streets and parks, because they are not precievable from inside the tunnel and are readily (and more accurately) available in other media (such as the official pdf maps). It would also clutter the track path on the diagram, as most Lisbon subway tunnels run under (not only undercross) major streets and avenues. In the case of this unusual crossing, the small street below is relevant, as it is clearly seen from inside the subway train even by the most unware passenger (at least with daylight); the big avenue above (that runs above the tunnel for three stations) is not.

Finally, the discussion at Talk:BSicon/Icon topology and semantics#"No bridges below surface"— NOT! shows not only that there are underground bridges in real life yessiree, for which this icon is the only possible representation, but also that there is a building consensus that the bridge icon in things such as  (utKRZto) and  (utKRZtu) can be used to express which tunnel runs above which other, regardless of vertical distance, leaving  (utKRZt) for unknown stack order or actual underground flat crossing. And I'm adding myself to this consensus.

-- Tuválkin ✉ 11:18, 27 December 2011 (UTC)

Points well made. Does any of this explanation appear in the article? (My knowledge of Portuguese is zero.) I have though, however, taken the liberty of uploading a revised version of the icon with a shorter bridge, which – I doubt that you will disagree – more accurately depicts the actual situation. Useddenim (talk) 20:35, 27 December 2011 (UTC)

There’s no text yet about this feature of the track — as also not about many other such features. It is easy to just pen it out, but you know about O.R. and sources. But of course there will be. The considerations about what's featured and not in the diagrams will be added to a special version or section of the Legend page — also a work in progress. (As the Portuguese classical railway network is being avidly dismantled by a 3rd wave of short sighted politicians, we have been focusing on recording the history of those perishing surface rural lines, leaving the relatively safe underground metropolitan rail in the back burner, so to say, for a while.)

I have no issue with the smaller bridge you uploaded; what I had before was mindlessly taken from  (RP2oRP2) which in turn comes from  (BRÜCKE). However, I’m sure that the matter of bridge design, incl. size(s), should be decided upon based on a generalized discussion we should hold some day, not inspired by this one single case.

-- Tuválkin ✉ 23:39, 27 December 2011 (UTC)

In general—but like most things about BS icons, there are no hard and fast rules—the longer bridges are used in plain  (BRÜCKE) and water  (WBRÜCKE) icons, while the shorter ones are employed with rail crossings  (KRZo) etc. The road/rail combinations are all over the place. Useddenim (talk) 00:18, 28 December 2011 (UTC)