How do you get Ghost while waiting for the funicular in Picus?
Solution 1:
To my recollection, I did get Ghost in this room. To do so, as soon as I hit the switch I activated stealth and crouch-walked into the nearest hole in the floor, where a floorboard had been removed. I hid inside this vent area until the funicular finally arrived, and then activated stealth, went into the funicular and closed it to complete the objective. No one was harmed, and nobody saw me.
Solution 2:
I got it too; I was quite fortunate to have several gas mines + templates.
In total I laid down four mines. One gas mine at both entrances, and concussion mines just to the right side of where the closest mine would have been. I then just crouched behind the block and managed to stealth into the funicular. I did it my first attempt without reloading, so it was quite an easy one.
If you don't have gas mines, I think the vent strategy would work best.