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

[Colin Smale]

  On 04/09/2010 06:53, Steve Bennett wrote:
> 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.
If you mean "which train do I catch to get from A to B" the the presence 
of the tracks says nothing about the route of the train services. On the 
other hand if you are working for the train (infrastructure) company 
planning a train path from A to B you will need to know all the details 
about the individual tracks and where they connect. Multiple train 
tracks are definitely conceptually different to multiple lanes on a 
motorway. In a car on the motorway you can change lanes wherever you 
like - all the lanes are normally equivalent to each other (exceptions 
include crawler lanes, carpool lanes etc etc). Trains are only able to 
change tracks where there are points/switches.

Colin