. =empty space ,
F = Floor,
W = Wall,
1 = Trackramp NS,
2 = Trackramp NW,
3 = Trackramp NE,
4 = Trackramp SW,
5 = Trackramp SE,
H = hatchcover
Lvl1:
enemies enter from north, go to south
FWWF
FWWF
F11F
W23W
W23W
-as many as you like-
W23W
W23W
W23W
WFFW
WFFW
lvl2:
WWWW
4235
4..5
4WW5
4WW5
-as many as you like-
4W44
4W4W
4HHW
53WW
WWWW
Put a minecart on each hatch cover, and open the hatches to start the system and close them to stop it.
Be careful, this design is not buildingdestroyer safe ^^
If you want to achieve that, change one row of:
W23W onto the lower floor into F11F (important that its floors, not ramps)
and the corresponding row above from 4WW5 into .WW.
Better do this close to the southern end of the system.
This prevents any BD to reach the hatches, and the minecarts can jump over the gaps, without issues, if they have enough speed (that's why it should be done close to the southern end)