In the course of building an above-ground shotgun, I have run into a problem with carts refusing to follow tracks downwards.
The situation is as thus:
___VO Key:
OVO _:Track
OVO O:Wall (With track on top)
OVO V:Down Ramp
OVO
The contents of the cart always ends up falling onto the 2nd lowest V.
Can anyone help work out how to keep the cart from derailing.
Are the carts going up (right to left) or down (left to right) in your diagram? Also, the diagram is a bit confusing. There should be a ramp on each level, and then open space adjacent to each ramp (above the ramp on the level below), right?
On to helpful advice: the derailment could easily be happening somewhere other than where you describe, too. It's possible for a cart to derail slightly (acquire a slowish velocity perpendicular to the track motion), but still be traveling much more quickly parallel to the track, so it will take several tiles to appear to go off the track.
Could you diagram your setup more completely? Also, definitely read through the comprehensive
Minecart Education Thread by Larix and check whether any of the conditions for derailment he describes apply to your setup. (Then take up the harder task of finding whether any "checkpoint" mechanics are complicating things.)
If nothing else, you can load up the save and advance it tick by tick, checking the velocity properties of the minecart at each tick using dfhack. You should be able to identify the tick at which it derails by noticing when it is moving in some way not parallel to the track direction, and also when exactly it ejects its contents.