NWDI Queries

Hello,

I was reading blogs and forums about NWDI and had certain questions regarding it:

1) What is a track used for ?(Is it assigned a physical disk space or is just a logical container)

2) The runtime systems to which NWDI is connected are DEV,QAT and PRO then where does this Consolidation system fitin which I think is not a Runtime system.

3) What is the use of creating a second(Maintenance) track ?

Any help would be highly appreciated..