0013555: Discovered with AI: rider stuck forever on a cart hanging over another cart - Dwarf Fortress Bug Tracker

ID	Project	Category	View Status	Date Submitted	Last Update

0013555	Dwarf Fortress	Technical -- General	public	2026-10-02 11:51	2026-10-02 11:51

Reporter	LucaSammartino	Assigned To
Priority	low	Severity	minor	Reproducibility	always
Status	new	Resolution	open
Product Version	53.16

Summary	0013555: Discovered with AI: rider stuck forever on a cart hanging over another cart
Description	What happens. A dwarf riding a minecart can end up in a cart that freezes in mid-air above another cart standing on a ramp tile. The cart never comes down, and the dwarf never gets off. He is not hurt, but he starves: in my test he died of thirst about 80,000 ticks later (roughly 55 game days). Version Dwarf Fortress 53.16, DFHack 53.16-r1.1, macOS, with a Steam Workshop-free vanilla save. What I saw (single run). Cart: frozen in mid-air above the parked cart, with its speed number unchanged at 18,800. The position never changed. Dwarf: unit 851 stayed in the same tile as the cart, still holding the job PushTrackVehicle. No wounds and full blood throughout. Counters: hunger, thirst and sleep all just kept counting up. Death: thirst reached 75,000 and he died at about frame 80,140, with no wounds and the cart still frozen. Ticks after the hang started Thirst timer Status 0000010:0000005,000 3,930 alive 0000040:0000044,000 42,930 alive 0000017:0000056,000 54,930 alive 0000033:0000076,000 74,930 alive 0000076:0000080,000 75,000 dead
Steps To Reproduce	How to reproduce, in plain terms. Dig a ramp with no track on it. It should be one tile that slopes down one level, with a flat floor on the upper side and another flat floor below. Put a second, parked cart on the ramp tile itself. Get a dwarf riding a cart (route with Ride departure, as I did) and make that cart roll toward the ramp from the upper floor, at about 24,000 speed. Anywhere from 22,500 up works; so do a few narrow bands lower down (for example 20,900). The riding cart reaches the top of the ramp and freezes above the parked cart instead of coming down. Wait and watch the dwarf. I could not make a ridden cart reach the ramp at that speed by normal play. Pushed carts only get about 19,700. I got it by moving the cart to the ramp with a DFHack script (mountain-planner-set place and velocity). The rider stayed attached through the move. So the bug itself is certain, but the "natural" way a player would trigger it is not shown. The speed band also exists for carts launched by rollers, which reach it easily.
Additional Information	Why it happens. At that speed the game freezes the cart above an occupied landing tile and waits for the tile to clear. The wiki's Stacking section describes this wait. When the cart underneath can't move away (here it was too heavy or not hit hard enough), the wait is endless, and nothing ends the rider's job.
Tags	minecarts

Date Modified	Username	Field	Change
2026-10-02 11:51	LucaSammartino	New Issue
2026-10-02 11:51	LucaSammartino	Tag Attached: minecarts