FA-67301 / Railway interlocking logic / Open access

Automatic route setting arbitration: arbitration order · case 01

A lower-class train wins a conflicting route over a higher-class train.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Candidates are ordered by arrival time only.

VERIFIED REPAIR

Order by class, then scheduled time, then id.

Unsuccessful approach: Putting schedule before class still lets an earlier freight beat an express.

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.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    now = x['now']
    cand = [t for t in x['trains'] if t['eta'] - now <= x['lookahead_s']]
    cand.sort(key=lambda t: (t['eta'], t['id']))
    pairs = set()
    for a, b in x['conflicts']:
        pairs.add((a, b))
        pairs.add((b, a))
    granted = []
    routes = []
    for t in cand:
        if any(t['route'] == r or (t['route'], r) in pairs for r in routes):
            continue
        granted.append(t['id'])
        routes.append(t['route'])
    return granted
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 4', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 100, 'eta': 80, 'route': 'R5'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R1', 'R2'], ['R3', 'R2'], ['R4', 'R5']]}, ['8A01', '2A00']), ('sampled regression 3', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '3A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 160, 'route': 'R4'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 100, 'route': 'R4'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R1'}, {'id': '9A04', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '7A05', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R3'}], 'conflicts': [['R2', 'R1'], ['R1', 'R5'], ['R3', 'R4']]}, ['6A02', '3A00']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('control 1', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 120, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R4', 'R3'], ['R2', 'R3'], ['R4', 'R5'], ['R2', 'R1']]}, []), ('control 7', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R3', 'R2']]}, ['9A01']), ('sampled regression 10', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '1A00', 'cls': 1, 'sched': 200, 'eta': 220, 'route': 'R1'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '7A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '4A03', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '1A04', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A05', 'cls': 3, 'sched': 150, 'eta': 400, 'route': 'R4'}], 'conflicts': [['R2', 'R1'], ['R3', 'R4'], ['R5', 'R4']]}, ['1A04', '1A00'])], [('regression: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 15', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 180, 'route': 'R5'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 130, 'route': 'R5'}, {'id': '5A03', 'cls': 3, 'sched': 120, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R2', 'R1'], ['R4', 'R5'], ['R1', 'R5']]}, ['7A02', '6A01']), ('sampled regression 18', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R1', 'R2'], ['R4', 'R3']]}, ['9A00']), ('boundary: conflict listed in reverse order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R2'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R1'}]}, ['1A01']), ('control 12', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '8A00', 'cls': 1, 'sched': 100, 'eta': 180, 'route': 'R3'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R3', 'R4']]}, ['8A00', '8A01']), ('control 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('sampled regression 24', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R4'}, {'id': '4A01', 'cls': 3, 'sched': 200, 'eta': 400, 'route': 'R5'}, {'id': '8A02', 'cls': 2, 'sched': 100, 'eta': 180, 'route': 'R2'}, {'id': '3A03', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R5'}], 'conflicts': [['R2', 'R3'], ['R1', 'R5'], ['R1', 'R2']]}, ['8A02', '5A00'])], [('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 25', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R2'}, {'id': '7A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R2'}, {'id': '1A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3']]}, ['2A00', '2A02']), ('sampled regression 33', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '7A00', 'cls': 1, 'sched': 200, 'eta': 130, 'route': 'R2'}, {'id': '1A01', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R3'}, {'id': '9A02', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3'], ['R4', 'R5']]}, ['7A00']), ('boundary: reverse-listed conflict granted in reverse', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R3', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R2'}]}, ['1A01']), ('boundary: two trains for one route', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R3'}]}, ['1A01']), ('sampled regression 23', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 200, 'eta': 180, 'route': 'R4'}, {'id': '1A01', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R2'}, {'id': '5A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R5'}, {'id': '2A03', 'cls': 2, 'sched': 150, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1']]}, ['9A00', '5A02', '2A03']), ('sampled regression 26', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '7A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 130, 'route': 'R1'}, {'id': '7A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '1A05', 'cls': 2, 'sched': 150, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R1', 'R5']]}, ['9A00', '7A04']), ('control 29', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '6A00', 'cls': 2, 'sched': 200, 'eta': 80, 'route': 'R5'}, {'id': '8A01', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R1'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '2A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R4', 'R3'], ['R2', 'R1'], ['R3', 'R2']]}, ['6A00'])], [('regression: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 35', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}, {'id': '1A01', 'cls': 2, 'sched': 100, 'eta': 100, 'route': 'R4'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R3'}, {'id': '8A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R4'}], 'conflicts': [['R1', 'R2'], ['R2', 'R3'], ['R1', 'R5']]}, ['1A02', '1A01']), ('sampled regression 40', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 120, 'eta': 180, 'route': 'R4'}, {'id': '2A01', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R4'}, {'id': '8A02', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R3'}, {'id': '1A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A05', 'cls': 3, 'sched': 120, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R1', 'R5'], ['R2', 'R3'], ['R1', 'R2'], ['R3', 'R4']]}, ['8A02', '3A05']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 34', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '6A01', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R4', 'R3']]}, ['2A00']), ('control 37', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '4A00', 'cls': 3, 'sched': 120, 'eta': 400, 'route': 'R4'}, {'id': '1A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R4'}, {'id': '6A02', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A03', 'cls': 2, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '1A04', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R2'}, {'id': '6A05', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1'], ['R3', 'R4']]}, ['1A01']), ('control 43', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '7A00', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R5'}, {'id': '3A01', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R5', 'R4']]}, ['7A00'])], [('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('sampled regression 58', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R4'}, {'id': '7A02', 'cls': 3, 'sched': 200, 'eta': 180, 'route': 'R1'}, {'id': '8A03', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R5'}, {'id': '7A04', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}, {'id': '6A05', 'cls': 3, 'sched': 200, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R4', 'R3'], ['R1', 'R2']]}, ['8A03', '9A01', '6A05']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('sampled regression 48', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 100, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R4', 'R5'], ['R3', 'R4'], ['R1', 'R2']]}, ['5A00', '2A01']), ('control 51', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '6A01', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '3A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R4'}, {'id': '6A03', 'cls': 2, 'sched': 100, 'eta': 400, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R4', 'R5']]}, ['3A02']), ('sampled regression 54', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '7A00', 'cls': 3, 'sched': 150, 'eta': 100, 'route': 'R2'}, {'id': '5A01', 'cls': 3, 'sched': 150, 'eta': 400, 'route': 'R3'}, {'id': '9A02', 'cls': 1, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '7A03', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R3'}, {'id': '4A04', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R3'}], 'conflicts': [['R3', 'R2'], ['R1', 'R5'], ['R4', 'R3']]}, ['9A02', '7A00'])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: class beats schedule	`['2A01']`	`['1A02']`	Failed
sampled regression 4	`['7A02', '8A01']`	`['8A01', '2A00']`	Failed
sampled regression 3	`['1A03', '6A02']`	`['6A02', '3A00']`	Failed
boundary: eta exactly at the lookahead	`['1A01']`	`['1A01']`	Passed
boundary: overdue train	`['2A01']`	`['2A01']`	Passed
control 1	`[]`	`[]`	Passed
control 7	`['9A01']`	`['9A01']`	Passed
sampled regression 10	`['6A01', '1A00']`	`['1A04', '1A00']`	Failed

SHA-256 / 592078b5ab05aceded9d83c1c17ee05ac3127d40aac203b89cee54a32eda98ff

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    now = x['now']
    cand = [t for t in x['trains'] if t['eta'] - now <= x['lookahead_s']]
    cand.sort(key=lambda t: (t['sched'], t['cls'], t['id']))
    pairs = set()
    for a, b in x['conflicts']:
        pairs.add((a, b))
        pairs.add((b, a))
    granted = []
    routes = []
    for t in cand:
        if any(t['route'] == r or (t['route'], r) in pairs for r in routes):
            continue
        granted.append(t['id'])
        routes.append(t['route'])
    return granted
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 4', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 100, 'eta': 80, 'route': 'R5'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R1', 'R2'], ['R3', 'R2'], ['R4', 'R5']]}, ['8A01', '2A00']), ('sampled regression 3', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '3A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 160, 'route': 'R4'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 100, 'route': 'R4'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R1'}, {'id': '9A04', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '7A05', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R3'}], 'conflicts': [['R2', 'R1'], ['R1', 'R5'], ['R3', 'R4']]}, ['6A02', '3A00']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('control 1', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 120, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R4', 'R3'], ['R2', 'R3'], ['R4', 'R5'], ['R2', 'R1']]}, []), ('control 7', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R3', 'R2']]}, ['9A01']), ('sampled regression 10', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '1A00', 'cls': 1, 'sched': 200, 'eta': 220, 'route': 'R1'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '7A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '4A03', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '1A04', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A05', 'cls': 3, 'sched': 150, 'eta': 400, 'route': 'R4'}], 'conflicts': [['R2', 'R1'], ['R3', 'R4'], ['R5', 'R4']]}, ['1A04', '1A00'])], [('regression: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 15', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 180, 'route': 'R5'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 130, 'route': 'R5'}, {'id': '5A03', 'cls': 3, 'sched': 120, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R2', 'R1'], ['R4', 'R5'], ['R1', 'R5']]}, ['7A02', '6A01']), ('sampled regression 18', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R1', 'R2'], ['R4', 'R3']]}, ['9A00']), ('boundary: conflict listed in reverse order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R2'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R1'}]}, ['1A01']), ('control 12', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '8A00', 'cls': 1, 'sched': 100, 'eta': 180, 'route': 'R3'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R3', 'R4']]}, ['8A00', '8A01']), ('control 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('sampled regression 24', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R4'}, {'id': '4A01', 'cls': 3, 'sched': 200, 'eta': 400, 'route': 'R5'}, {'id': '8A02', 'cls': 2, 'sched': 100, 'eta': 180, 'route': 'R2'}, {'id': '3A03', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R5'}], 'conflicts': [['R2', 'R3'], ['R1', 'R5'], ['R1', 'R2']]}, ['8A02', '5A00'])], [('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 25', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R2'}, {'id': '7A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R2'}, {'id': '1A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3']]}, ['2A00', '2A02']), ('sampled regression 33', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '7A00', 'cls': 1, 'sched': 200, 'eta': 130, 'route': 'R2'}, {'id': '1A01', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R3'}, {'id': '9A02', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3'], ['R4', 'R5']]}, ['7A00']), ('boundary: reverse-listed conflict granted in reverse', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R3', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R2'}]}, ['1A01']), ('boundary: two trains for one route', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R3'}]}, ['1A01']), ('sampled regression 23', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 200, 'eta': 180, 'route': 'R4'}, {'id': '1A01', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R2'}, {'id': '5A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R5'}, {'id': '2A03', 'cls': 2, 'sched': 150, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1']]}, ['9A00', '5A02', '2A03']), ('sampled regression 26', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '7A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 130, 'route': 'R1'}, {'id': '7A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '1A05', 'cls': 2, 'sched': 150, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R1', 'R5']]}, ['9A00', '7A04']), ('control 29', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '6A00', 'cls': 2, 'sched': 200, 'eta': 80, 'route': 'R5'}, {'id': '8A01', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R1'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '2A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R4', 'R3'], ['R2', 'R1'], ['R3', 'R2']]}, ['6A00'])], [('regression: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 35', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}, {'id': '1A01', 'cls': 2, 'sched': 100, 'eta': 100, 'route': 'R4'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R3'}, {'id': '8A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R4'}], 'conflicts': [['R1', 'R2'], ['R2', 'R3'], ['R1', 'R5']]}, ['1A02', '1A01']), ('sampled regression 40', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 120, 'eta': 180, 'route': 'R4'}, {'id': '2A01', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R4'}, {'id': '8A02', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R3'}, {'id': '1A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A05', 'cls': 3, 'sched': 120, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R1', 'R5'], ['R2', 'R3'], ['R1', 'R2'], ['R3', 'R4']]}, ['8A02', '3A05']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 34', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '6A01', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R4', 'R3']]}, ['2A00']), ('control 37', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '4A00', 'cls': 3, 'sched': 120, 'eta': 400, 'route': 'R4'}, {'id': '1A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R4'}, {'id': '6A02', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A03', 'cls': 2, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '1A04', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R2'}, {'id': '6A05', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1'], ['R3', 'R4']]}, ['1A01']), ('control 43', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '7A00', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R5'}, {'id': '3A01', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R5', 'R4']]}, ['7A00'])], [('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('sampled regression 58', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R4'}, {'id': '7A02', 'cls': 3, 'sched': 200, 'eta': 180, 'route': 'R1'}, {'id': '8A03', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R5'}, {'id': '7A04', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}, {'id': '6A05', 'cls': 3, 'sched': 200, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R4', 'R3'], ['R1', 'R2']]}, ['8A03', '9A01', '6A05']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('sampled regression 48', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 100, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R4', 'R5'], ['R3', 'R4'], ['R1', 'R2']]}, ['5A00', '2A01']), ('control 51', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '6A01', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '3A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R4'}, {'id': '6A03', 'cls': 2, 'sched': 100, 'eta': 400, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R4', 'R5']]}, ['3A02']), ('sampled regression 54', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '7A00', 'cls': 3, 'sched': 150, 'eta': 100, 'route': 'R2'}, {'id': '5A01', 'cls': 3, 'sched': 150, 'eta': 400, 'route': 'R3'}, {'id': '9A02', 'cls': 1, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '7A03', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R3'}, {'id': '4A04', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R3'}], 'conflicts': [['R3', 'R2'], ['R1', 'R5'], ['R4', 'R3']]}, ['9A02', '7A00'])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: class beats schedule	`['2A01']`	`['1A02']`	Failed
sampled regression 4	`['8A01', '7A02']`	`['8A01', '2A00']`	Failed
sampled regression 3	`['2A01', '3A00']`	`['6A02', '3A00']`	Failed
boundary: eta exactly at the lookahead	`['1A01']`	`['1A01']`	Passed
boundary: overdue train	`['2A01']`	`['2A01']`	Passed
control 1	`[]`	`[]`	Passed
control 7	`['9A01']`	`['9A01']`	Passed
sampled regression 10	`['4A03', '1A00']`	`['1A04', '1A00']`	Failed

SHA-256 / 21ec167dfa15108841b0e38fb655e1d4736d437738508758e9347a99b5bb03c4

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(x):
    now = x['now']
    cand = [t for t in x['trains'] if t['eta'] - now <= x['lookahead_s']]
    cand.sort(key=lambda t: (t['cls'], t['sched'], t['id']))
    pairs = set()
    for a, b in x['conflicts']:
        pairs.add((a, b))
        pairs.add((b, a))
    granted = []
    routes = []
    for t in cand:
        if any(t['route'] == r or (t['route'], r) in pairs for r in routes):
            continue
        granted.append(t['id'])
        routes.append(t['route'])
    return granted
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 4', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R3'}, {'id': '8A01', 'cls': 1, 'sched': 100, 'eta': 80, 'route': 'R5'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R1', 'R2'], ['R3', 'R2'], ['R4', 'R5']]}, ['8A01', '2A00']), ('sampled regression 3', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '3A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 160, 'route': 'R4'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 100, 'route': 'R4'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R1'}, {'id': '9A04', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '7A05', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R3'}], 'conflicts': [['R2', 'R1'], ['R1', 'R5'], ['R3', 'R4']]}, ['6A02', '3A00']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('control 1', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 120, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R4', 'R3'], ['R2', 'R3'], ['R4', 'R5'], ['R2', 'R1']]}, []), ('control 7', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R3', 'R2']]}, ['9A01']), ('sampled regression 10', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '1A00', 'cls': 1, 'sched': 200, 'eta': 220, 'route': 'R1'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '7A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '4A03', 'cls': 3, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '1A04', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A05', 'cls': 3, 'sched': 150, 'eta': 400, 'route': 'R4'}], 'conflicts': [['R2', 'R1'], ['R3', 'R4'], ['R5', 'R4']]}, ['1A04', '1A00'])], [('regression: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 15', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 200, 'eta': 180, 'route': 'R5'}, {'id': '6A01', 'cls': 3, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '7A02', 'cls': 3, 'sched': 100, 'eta': 130, 'route': 'R5'}, {'id': '5A03', 'cls': 3, 'sched': 120, 'eta': 160, 'route': 'R1'}], 'conflicts': [['R2', 'R1'], ['R4', 'R5'], ['R1', 'R5']]}, ['7A02', '6A01']), ('sampled regression 18', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R1', 'R2'], ['R4', 'R3']]}, ['9A00']), ('boundary: conflict listed in reverse order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R2'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R1'}]}, ['1A01']), ('control 12', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '8A00', 'cls': 1, 'sched': 100, 'eta': 180, 'route': 'R3'}, {'id': '8A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R2'}], 'conflicts': [['R3', 'R4']]}, ['8A00', '8A01']), ('control 21', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R5'}, {'id': '3A02', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R2'}], 'conflicts': [['R5', 'R1'], ['R4', 'R3'], ['R5', 'R4'], ['R1', 'R2']]}, ['7A01', '3A02']), ('sampled regression 24', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 160, 'route': 'R4'}, {'id': '4A01', 'cls': 3, 'sched': 200, 'eta': 400, 'route': 'R5'}, {'id': '8A02', 'cls': 2, 'sched': 100, 'eta': 180, 'route': 'R2'}, {'id': '3A03', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R5'}], 'conflicts': [['R2', 'R3'], ['R1', 'R5'], ['R1', 'R2']]}, ['8A02', '5A00'])], [('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 25', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R1'}, {'id': '7A01', 'cls': 1, 'sched': 150, 'eta': 80, 'route': 'R2'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R2'}, {'id': '7A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R2'}, {'id': '1A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3']]}, ['2A00', '2A02']), ('sampled regression 33', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '7A00', 'cls': 1, 'sched': 200, 'eta': 130, 'route': 'R2'}, {'id': '1A01', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R3'}, {'id': '9A02', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R2', 'R3'], ['R4', 'R3'], ['R4', 'R5']]}, ['7A00']), ('boundary: reverse-listed conflict granted in reverse', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R3', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R2'}]}, ['1A01']), ('boundary: two trains for one route', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R3'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 120, 'route': 'R3'}]}, ['1A01']), ('sampled regression 23', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 200, 'eta': 180, 'route': 'R4'}, {'id': '1A01', 'cls': 2, 'sched': 200, 'eta': 220, 'route': 'R2'}, {'id': '5A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R5'}, {'id': '2A03', 'cls': 2, 'sched': 150, 'eta': 80, 'route': 'R2'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1']]}, ['9A00', '5A02', '2A03']), ('sampled regression 26', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '9A00', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '7A01', 'cls': 2, 'sched': 100, 'eta': 220, 'route': 'R4'}, {'id': '2A02', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}, {'id': '1A03', 'cls': 3, 'sched': 150, 'eta': 130, 'route': 'R1'}, {'id': '7A04', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '1A05', 'cls': 2, 'sched': 150, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R1', 'R5']]}, ['9A00', '7A04']), ('control 29', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '6A00', 'cls': 2, 'sched': 200, 'eta': 80, 'route': 'R5'}, {'id': '8A01', 'cls': 2, 'sched': 120, 'eta': 220, 'route': 'R1'}, {'id': '6A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '2A03', 'cls': 1, 'sched': 200, 'eta': 400, 'route': 'R3'}], 'conflicts': [['R5', 'R4'], ['R4', 'R3'], ['R2', 'R1'], ['R3', 'R2']]}, ['6A00'])], [('regression: late running train keeps schedule order', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 150, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 120, 'eta': 105, 'route': 'R2'}]}, ['1A01']), ('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 35', {'now': 100, 'lookahead_s': 120, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 100, 'eta': 80, 'route': 'R3'}, {'id': '1A01', 'cls': 2, 'sched': 100, 'eta': 100, 'route': 'R4'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 160, 'route': 'R3'}, {'id': '8A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 120, 'eta': 400, 'route': 'R4'}], 'conflicts': [['R1', 'R2'], ['R2', 'R3'], ['R1', 'R5']]}, ['1A02', '1A01']), ('sampled regression 40', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 120, 'eta': 180, 'route': 'R4'}, {'id': '2A01', 'cls': 1, 'sched': 100, 'eta': 400, 'route': 'R4'}, {'id': '8A02', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R3'}, {'id': '1A03', 'cls': 2, 'sched': 200, 'eta': 100, 'route': 'R3'}, {'id': '8A04', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A05', 'cls': 3, 'sched': 120, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R1', 'R5'], ['R2', 'R3'], ['R1', 'R2'], ['R3', 'R4']]}, ['8A02', '3A05']), ('boundary: conflict with an earlier grant', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R5']], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 110, 'eta': 120, 'route': 'R4'}, {'id': '1A03', 'cls': 1, 'sched': 130, 'eta': 130, 'route': 'R5'}]}, ['1A01', '1A02']), ('sampled regression 34', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '2A00', 'cls': 2, 'sched': 150, 'eta': 160, 'route': 'R5'}, {'id': '6A01', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}], 'conflicts': [['R4', 'R3']]}, ['2A00']), ('control 37', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '4A00', 'cls': 3, 'sched': 120, 'eta': 400, 'route': 'R4'}, {'id': '1A01', 'cls': 1, 'sched': 150, 'eta': 100, 'route': 'R4'}, {'id': '6A02', 'cls': 2, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '3A03', 'cls': 2, 'sched': 150, 'eta': 220, 'route': 'R5'}, {'id': '1A04', 'cls': 3, 'sched': 120, 'eta': 220, 'route': 'R2'}, {'id': '6A05', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R1', 'R5'], ['R2', 'R1'], ['R3', 'R4']]}, ['1A01']), ('control 43', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '7A00', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R5'}, {'id': '3A01', 'cls': 1, 'sched': 150, 'eta': 180, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R5', 'R4']]}, ['7A00'])], [('regression: class beats schedule', {'now': 100, 'lookahead_s': 60, 'conflicts': [['R1', 'R2']], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 100, 'eta': 110, 'route': 'R1'}, {'id': '1A02', 'cls': 1, 'sched': 150, 'eta': 150, 'route': 'R2'}]}, ['1A02']), ('sampled regression 45', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '6A00', 'cls': 3, 'sched': 150, 'eta': 180, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R1'}, {'id': '2A02', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R1'}, {'id': '5A03', 'cls': 1, 'sched': 120, 'eta': 160, 'route': 'R2'}, {'id': '9A04', 'cls': 3, 'sched': 200, 'eta': 130, 'route': 'R1'}, {'id': '5A05', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R1'}], 'conflicts': [['R5', 'R4'], ['R3', 'R2'], ['R1', 'R5'], ['R3', 'R4']]}, ['5A03', '5A05']), ('sampled regression 58', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '8A00', 'cls': 3, 'sched': 100, 'eta': 160, 'route': 'R5'}, {'id': '9A01', 'cls': 3, 'sched': 120, 'eta': 80, 'route': 'R4'}, {'id': '7A02', 'cls': 3, 'sched': 200, 'eta': 180, 'route': 'R1'}, {'id': '8A03', 'cls': 1, 'sched': 120, 'eta': 130, 'route': 'R5'}, {'id': '7A04', 'cls': 2, 'sched': 200, 'eta': 130, 'route': 'R5'}, {'id': '6A05', 'cls': 3, 'sched': 200, 'eta': 180, 'route': 'R1'}], 'conflicts': [['R4', 'R3'], ['R1', 'R2']]}, ['8A03', '9A01', '6A05']), ('boundary: eta exactly at the lookahead', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '1A01', 'cls': 1, 'sched': 100, 'eta': 160, 'route': 'R1'}]}, ['1A01']), ('boundary: overdue train', {'now': 100, 'lookahead_s': 60, 'conflicts': [], 'trains': [{'id': '2A01', 'cls': 2, 'sched': 60, 'eta': 70, 'route': 'R2'}]}, ['2A01']), ('sampled regression 48', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 2, 'sched': 120, 'eta': 100, 'route': 'R1'}, {'id': '2A01', 'cls': 3, 'sched': 100, 'eta': 100, 'route': 'R3'}], 'conflicts': [['R4', 'R5'], ['R3', 'R4'], ['R1', 'R2']]}, ['5A00', '2A01']), ('control 51', {'now': 100, 'lookahead_s': 80, 'trains': [{'id': '5A00', 'cls': 3, 'sched': 150, 'eta': 220, 'route': 'R4'}, {'id': '6A01', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R2'}, {'id': '3A02', 'cls': 2, 'sched': 120, 'eta': 160, 'route': 'R4'}, {'id': '6A03', 'cls': 2, 'sched': 100, 'eta': 400, 'route': 'R2'}], 'conflicts': [['R3', 'R2'], ['R4', 'R5']]}, ['3A02']), ('sampled regression 54', {'now': 100, 'lookahead_s': 60, 'trains': [{'id': '7A00', 'cls': 3, 'sched': 150, 'eta': 100, 'route': 'R2'}, {'id': '5A01', 'cls': 3, 'sched': 150, 'eta': 400, 'route': 'R3'}, {'id': '9A02', 'cls': 1, 'sched': 100, 'eta': 130, 'route': 'R4'}, {'id': '7A03', 'cls': 1, 'sched': 120, 'eta': 400, 'route': 'R3'}, {'id': '4A04', 'cls': 3, 'sched': 120, 'eta': 180, 'route': 'R3'}], 'conflicts': [['R3', 'R2'], ['R1', 'R5'], ['R4', 'R3']]}, ['9A02', '7A00'])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
regression: class beats schedule	`['1A02']`	`['1A02']`	Passed
sampled regression 4	`['8A01', '2A00']`	`['8A01', '2A00']`	Passed
sampled regression 3	`['6A02', '3A00']`	`['6A02', '3A00']`	Passed
boundary: eta exactly at the lookahead	`['1A01']`	`['1A01']`	Passed
boundary: overdue train	`['2A01']`	`['2A01']`	Passed
control 1	`[]`	`[]`	Passed
control 7	`['9A01']`	`['9A01']`	Passed
sampled regression 10	`['1A04', '1A00']`	`['1A04', '1A00']`	Passed

SHA-256 / b1a56cf5a2079ad44e04eae658ea2002f8c88742c78f7ae6a37fa61c980343eb

Verification & scope

Stipulated toy interlocking contract for a bounded teaching model; it makes no claim of conformance to any railway signalling standard and omits real safety cases. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:47:51.645372+00:00.

Case digest / 02877dd3dd74fb64cd6a152ab73cdc2491ab60d65820f4f58cdd3ace1cad71c6