FA-67300 / Railway interlocking logic / Member archive

Automatic route setting arbitration: lookahead window · case 05

An overdue train or one arriving exactly at the horizon gets no route.

Member previewVariant 5 · 3 implementations · 8 checks per implementation

Case contract

Trains whose eta is at most lookahead_s after now are candidates, including overdue trains (eta before now). Candidates are ordered by class (1 highest), then scheduled time, then id. Routes are granted greedily in that order; a candidate is skipped if its route equals or conflicts with (conflict pairs are unordered) any route already granted. Return granted train ids in grant order.

Why this case matters

Interlocking logic decides whether trains may be given authority; a wrong decision at this point either grants unsafe movements or strands traffic.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: eta exactly at the lookahead	`[]`	`["1A01"]`	Failed

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