1st design - the smallest loop I have created where pressure plate is still able to reset.
(8x4)Time for a minecart to complete one lap -
110 ticks Minecart starts at the top left corner going south.
The top left corner is accelerator made from S/W track ramps. These ramps require a wall on west side.
Track under pressure plate is E/W. At the right image is detail on how the track goes (don't forget some of those are ramps).
Doors are there only as an emergency stop.
To start the whole thing build hatch cover above the top left corner and place a forbined minecart on it. Then pull the lever.
Note that the minecart has to derail into the top left corner with some (high?) speed. I think that the minecart tries to go up the W ramp then loose all it energy (therefore there were no speed ups as mentioned before). Pushing cart on the 1st from the top right corner didn't work.
This setup works with doors and harch covers/grates. But they are mostly open because closed state remains only for cca 6 ticks (because minecart stays on the pressure plate for 4 ticks if I have counted correcly).
It also works with retracting spikes, bridges and floodgates but the minecarts has to pass 2 laps for these buildings to return to basic state.
2nd design - (8x6)
Time for a minecart to complete one lap -
170 ticksBecause on this bigger track the minecart was slowing with each lap I had to add another track ramp. It is brown N/W track ramp at the top which also require wall on the north side.
3rd design - (8x4+6x2)
Time for a minecart to complete one lap -
153 ticks4th design - (8x6)
Time for a minecart to complete one lap -
151 ticksThis one is perhaps the best one for the retracting spikes. It is very close to 140 ticks which spikes need to reset but it doesn't have that acceleration part after the brown track ramp. So if you fill this track with pressure plate the delay between them would be almost linear.
And that is pretty much everything that is worth mentioning here. Maybe it could be smaller with track crossing...
Next time I will create something with 200 ticks delay so I can create (anti-?)parallel atom-smashers.