[Tagging] Relation for saying "x is attached to y"?

[Steve Bennett]

On Fri, Sep 3, 2010 at 2:37 AM, M∡rtin Koppenhoefer
<dieterdreist at gmail.com> wrote:
> so you are talking about rendering?

Primarily, yes. But could be useful for other applications. For
example, to do public transport routing, you would want to operate at
the level of "the train line", not at the level of an individual
track.

>A rendering hint that these two
> ways might be rendered as one in lower zooms?

Yes, that's a primary use case.

> Do you want to have three ways in OSM to
> represent 2 tracks?

Yes, but this is just one example. Lanes of roads is another. Perhaps
someone will think of other examples.

Steve