Advanced drilling machine?

[Celador]

How does it work? I can't place it anywhere.

[Blacksmith]

First you will need place down 3 or more mine cart rails, then you can place it, once placed down, your dwarf's will begin filling the machine with rails and stone bridge's, it will auto place down rails as it moves along, and it will also auto place down stone bridges when needed.

[Celador]

Thanks, also apparently it can't be place on the surface? At least i was trying to place it there on tracks to figure it out first.