Switchback Sums

Merge freight into an exact 8 at the northwest depot, then an exact 16 at the southeast depot. Slide all cars along clear rail segments; equal cars join once per slide. Each successful slide must change axis: horizontal, then vertical, or vice versa. Two signal overrides let your next slide repeat the axis. No new cars arrive, so preserve all 24 freight units. Dispatch is free and removes only the exact scheduled load from its depot. Dark blocks split the rails. Finish both deliveries within 24 slides; planning and signal selection cost no slide. An unavailable move leaves the board unchanged. Keyboard: Tab and Enter/Space operate buttons; R restarts.