FA-67061 / Railway interlocking logic / Open access
ATP braking curve supervision: safety margin · case 01
The permitted speed is supervised against the danger point rather than the margin-reduced target.
ROOT CAUSE
The safety margin is not deducted from the distance to target.
VERIFIED REPAIR
Subtract the full margin and floor the distance at zero.
Unsuccessful approach: Deducting only half the margin still overstates the braking distance.
Case contract
Permitted speed at the train is sqrt(vt^2 + 2*a*d) with vt the target speed in m/s, a = decel_cms2/100 m/s^2 and d = max(distance - safety margin, 0); convert back to km/h, truncate to an integer (never round up) and cap at line speed. Action is brake if speed > permitted + brake margin, else warning if speed > permitted + warn margin, else none.
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
import math
N = 1
observations = []
def solve(x):
vt = x['target_kmh'] / 3.6
d = x['distance_m']
a = x['decel_cms2'] / 100
vp = math.sqrt(vt * vt + 2 * a * d) * 3.6
permitted = min(int(vp), x['line_kmh'])
v = x['speed_kmh']
if v > permitted + x['brake_margin_kmh']:
action = 'brake'
elif v > permitted + x['warn_margin_kmh']:
action = 'warning'
else:
action = 'none'
return {'permitted': permitted, 'action': action}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('sampled regression 4', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 136, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 45, 'action': 'brake'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: curve above line speed', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 150, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'brake'}), ('control 1', {'target_kmh': 0, 'distance_m': 0, 'safety_margin_m': 0, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 139, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('control 7', {'target_kmh': 40, 'distance_m': 2500, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 59, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 160, 'action': 'none'}), ('sampled regression 10', {'target_kmh': 20, 'distance_m': 40, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 33, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 27, 'action': 'warning'})], [('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 19', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 17, 'warn_margin_kmh': 3, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('sampled regression 2', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 122, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 50, 'action': 'brake'}), ('boundary: curve above line speed', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 150, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'brake'}), ('sampled regression 12', {'target_kmh': 40, 'distance_m': 600, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 133, 'warn_margin_kmh': 3, 'brake_margin_kmh': 15}, {'permitted': 128, 'action': 'warning'}), ('sampled regression 15', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 43, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 102, 'action': 'none'}), ('control 18', {'target_kmh': 60, 'distance_m': 1200, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 6, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'none'})], [('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('sampled regression 42', {'target_kmh': 40, 'distance_m': 40, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 115, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 43, 'action': 'brake'}), ('sampled regression 11', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 120, 'speed_kmh': 158, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 77, 'action': 'brake'}), ('boundary: warning boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 45, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 23', {'target_kmh': 60, 'distance_m': 100, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 13, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 67, 'action': 'none'}), ('control 26', {'target_kmh': 60, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 86, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 160, 'action': 'none'}), ('control 29', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 0, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 4, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 67, 'action': 'none'})], [('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: warning boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 45, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 54', {'target_kmh': 60, 'distance_m': 1200, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 118, 'warn_margin_kmh': 3, 'brake_margin_kmh': 8}, {'permitted': 137, 'action': 'none'}), ('sampled regression 23', {'target_kmh': 60, 'distance_m': 100, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 13, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 67, 'action': 'none'}), ('boundary: between warning and brake', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 48, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'warning'}), ('control 34', {'target_kmh': 0, 'distance_m': 0, 'safety_margin_m': 0, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 96, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('control 37', {'target_kmh': 20, 'distance_m': 2500, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 168, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 80, 'action': 'brake'}), ('control 41', {'target_kmh': 40, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 61, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 80, 'action': 'none'})], [('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('boundary: brake boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 50, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'warning'}), ('sampled regression 70', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 42, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 45, 'action': 'none'}), ('sampled regression 40', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 70, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 84, 'action': 'none'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 46', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 120, 'speed_kmh': 73, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 45, 'action': 'brake'}), ('control 49', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 148, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 160, 'action': 'none'}), ('control 52', {'target_kmh': 40, 'distance_m': 250, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 50, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 80, 'action': 'none'})]]
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: stop target inside the margin | {'action': 'none', 'permitted': 26} | {'action': 'warning', 'permitted': 0} | Failed |
| sampled regression 4 | {'action': 'brake', 'permitted': 50} | {'action': 'brake', 'permitted': 45} | Failed |
| boundary: target speed release | {'action': 'none', 'permitted': 40} | {'action': 'none', 'permitted': 40} | Passed |
| regression: curve below line speed | {'action': 'none', 'permitted': 104} | {'action': 'none', 'permitted': 99} | Failed |
| boundary: curve above line speed | {'action': 'brake', 'permitted': 120} | {'action': 'brake', 'permitted': 120} | Passed |
| control 1 | {'action': 'brake', 'permitted': 0} | {'action': 'brake', 'permitted': 0} | Passed |
| control 7 | {'action': 'none', 'permitted': 160} | {'action': 'none', 'permitted': 160} | Passed |
| sampled regression 10 | {'action': 'none', 'permitted': 33} | {'action': 'warning', 'permitted': 27} | Failed |
SHA-256 / a15407567bd6d8fd6f2bfea098cba534ad976d272b85cc62eb5a22c3d4036c34
2 / The unsuccessful fix
Exit 1"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
vt = x['target_kmh'] / 3.6
d = max(x['distance_m'], 0) - x['safety_margin_m'] // 2
a = x['decel_cms2'] / 100
vp = math.sqrt(vt * vt + 2 * a * d) * 3.6
permitted = min(int(vp), x['line_kmh'])
v = x['speed_kmh']
if v > permitted + x['brake_margin_kmh']:
action = 'brake'
elif v > permitted + x['warn_margin_kmh']:
action = 'warning'
else:
action = 'none'
return {'permitted': permitted, 'action': action}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('sampled regression 4', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 136, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 45, 'action': 'brake'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: curve above line speed', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 150, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'brake'}), ('control 1', {'target_kmh': 0, 'distance_m': 0, 'safety_margin_m': 0, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 139, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('control 7', {'target_kmh': 40, 'distance_m': 2500, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 59, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 160, 'action': 'none'}), ('sampled regression 10', {'target_kmh': 20, 'distance_m': 40, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 33, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 27, 'action': 'warning'})], [('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 19', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 17, 'warn_margin_kmh': 3, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('sampled regression 2', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 122, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 50, 'action': 'brake'}), ('boundary: curve above line speed', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 150, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'brake'}), ('sampled regression 12', {'target_kmh': 40, 'distance_m': 600, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 133, 'warn_margin_kmh': 3, 'brake_margin_kmh': 15}, {'permitted': 128, 'action': 'warning'}), ('sampled regression 15', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 43, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 102, 'action': 'none'}), ('control 18', {'target_kmh': 60, 'distance_m': 1200, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 6, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'none'})], [('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('sampled regression 42', {'target_kmh': 40, 'distance_m': 40, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 115, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 43, 'action': 'brake'}), ('sampled regression 11', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 120, 'speed_kmh': 158, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 77, 'action': 'brake'}), ('boundary: warning boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 45, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 23', {'target_kmh': 60, 'distance_m': 100, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 13, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 67, 'action': 'none'}), ('control 26', {'target_kmh': 60, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 86, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 160, 'action': 'none'}), ('control 29', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 0, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 4, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 67, 'action': 'none'})], [('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: warning boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 45, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 54', {'target_kmh': 60, 'distance_m': 1200, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 118, 'warn_margin_kmh': 3, 'brake_margin_kmh': 8}, {'permitted': 137, 'action': 'none'}), ('sampled regression 23', {'target_kmh': 60, 'distance_m': 100, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 13, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 67, 'action': 'none'}), ('boundary: between warning and brake', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 48, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'warning'}), ('control 34', {'target_kmh': 0, 'distance_m': 0, 'safety_margin_m': 0, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 96, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('control 37', {'target_kmh': 20, 'distance_m': 2500, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 168, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 80, 'action': 'brake'}), ('control 41', {'target_kmh': 40, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 61, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 80, 'action': 'none'})], [('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('boundary: brake boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 50, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'warning'}), ('sampled regression 70', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 42, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 45, 'action': 'none'}), ('sampled regression 40', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 70, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 84, 'action': 'none'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 46', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 120, 'speed_kmh': 73, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 45, 'action': 'brake'}), ('control 49', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 148, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 160, 'action': 'none'}), ('control 52', {'target_kmh': 40, 'distance_m': 250, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 50, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 80, 'action': 'none'})]]
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: stop target inside the margin | {'action': 'none', 'permitted': 16} | {'action': 'warning', 'permitted': 0} | Failed |
| sampled regression 4 | {'action': 'brake', 'permitted': 48} | {'action': 'brake', 'permitted': 45} | Failed |
| boundary: target speed release | {'action': 'brake', 'permitted': 33} | {'action': 'none', 'permitted': 40} | Failed |
| regression: curve below line speed | {'action': 'none', 'permitted': 102} | {'action': 'none', 'permitted': 99} | Failed |
| boundary: curve above line speed | {'action': 'brake', 'permitted': 120} | {'action': 'brake', 'permitted': 120} | Passed |
| control 1 | {'action': 'brake', 'permitted': 0} | {'action': 'brake', 'permitted': 0} | Passed |
| control 7 | {'action': 'none', 'permitted': 160} | {'action': 'none', 'permitted': 160} | Passed |
| sampled regression 10 | {'action': 'none', 'permitted': 30} | {'action': 'warning', 'permitted': 27} | Failed |
SHA-256 / 27bbd3a0721a92d4a936ea26d7c96ebac802a6a2fb77d6cfd105cf5fb5d1581b
3 / The verified repair
Exit 0"""Failure Map reference implementation. Python standard library only."""
import json
import math
N = 1
observations = []
def solve(x):
vt = x['target_kmh'] / 3.6
d = max(x['distance_m'] - x['safety_margin_m'], 0)
a = x['decel_cms2'] / 100
vp = math.sqrt(vt * vt + 2 * a * d) * 3.6
permitted = min(int(vp), x['line_kmh'])
v = x['speed_kmh']
if v > permitted + x['brake_margin_kmh']:
action = 'brake'
elif v > permitted + x['warn_margin_kmh']:
action = 'warning'
else:
action = 'none'
return {'permitted': permitted, 'action': action}
def check(label, actual, expected):
observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('sampled regression 4', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 136, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 45, 'action': 'brake'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: curve above line speed', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 150, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'brake'}), ('control 1', {'target_kmh': 0, 'distance_m': 0, 'safety_margin_m': 0, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 139, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('control 7', {'target_kmh': 40, 'distance_m': 2500, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 59, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 160, 'action': 'none'}), ('sampled regression 10', {'target_kmh': 20, 'distance_m': 40, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 33, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 27, 'action': 'warning'})], [('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 19', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 17, 'warn_margin_kmh': 3, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('sampled regression 2', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 122, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 50, 'action': 'brake'}), ('boundary: curve above line speed', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 150, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'brake'}), ('sampled regression 12', {'target_kmh': 40, 'distance_m': 600, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 160, 'speed_kmh': 133, 'warn_margin_kmh': 3, 'brake_margin_kmh': 15}, {'permitted': 128, 'action': 'warning'}), ('sampled regression 15', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 43, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 102, 'action': 'none'}), ('control 18', {'target_kmh': 60, 'distance_m': 1200, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 6, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 120, 'action': 'none'})], [('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('sampled regression 42', {'target_kmh': 40, 'distance_m': 40, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 115, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 43, 'action': 'brake'}), ('sampled regression 11', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 120, 'speed_kmh': 158, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 77, 'action': 'brake'}), ('boundary: warning boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 45, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 23', {'target_kmh': 60, 'distance_m': 100, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 13, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 67, 'action': 'none'}), ('control 26', {'target_kmh': 60, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 86, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 160, 'action': 'none'}), ('control 29', {'target_kmh': 0, 'distance_m': 250, 'safety_margin_m': 0, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 4, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 67, 'action': 'none'})], [('regression: curve below line speed', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 100, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 99, 'action': 'none'}), ('boundary: warning boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 45, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 54', {'target_kmh': 60, 'distance_m': 1200, 'safety_margin_m': 20, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 118, 'warn_margin_kmh': 3, 'brake_margin_kmh': 8}, {'permitted': 137, 'action': 'none'}), ('sampled regression 23', {'target_kmh': 60, 'distance_m': 100, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 13, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 67, 'action': 'none'}), ('boundary: between warning and brake', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 48, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'warning'}), ('control 34', {'target_kmh': 0, 'distance_m': 0, 'safety_margin_m': 0, 'decel_cms2': 70, 'line_kmh': 120, 'speed_kmh': 96, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 0, 'action': 'brake'}), ('control 37', {'target_kmh': 20, 'distance_m': 2500, 'safety_margin_m': 20, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 168, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 80, 'action': 'brake'}), ('control 41', {'target_kmh': 40, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 80, 'speed_kmh': 61, 'warn_margin_kmh': 5, 'brake_margin_kmh': 8}, {'permitted': 80, 'action': 'none'})], [('regression: stop target inside the margin', {'target_kmh': 0, 'distance_m': 40, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 10, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 0, 'action': 'warning'}), ('boundary: brake boundary', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 50, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'warning'}), ('sampled regression 70', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 42, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 45, 'action': 'none'}), ('sampled regression 40', {'target_kmh': 0, 'distance_m': 600, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 70, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 84, 'action': 'none'}), ('boundary: target speed release', {'target_kmh': 40, 'distance_m': 0, 'safety_margin_m': 50, 'decel_cms2': 70, 'line_kmh': 160, 'speed_kmh': 44, 'warn_margin_kmh': 5, 'brake_margin_kmh': 10}, {'permitted': 40, 'action': 'none'}), ('sampled regression 46', {'target_kmh': 0, 'distance_m': 100, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 120, 'speed_kmh': 73, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 45, 'action': 'brake'}), ('control 49', {'target_kmh': 0, 'distance_m': 2500, 'safety_margin_m': 50, 'decel_cms2': 50, 'line_kmh': 160, 'speed_kmh': 148, 'warn_margin_kmh': 5, 'brake_margin_kmh': 15}, {'permitted': 160, 'action': 'none'}), ('control 52', {'target_kmh': 40, 'distance_m': 250, 'safety_margin_m': 20, 'decel_cms2': 100, 'line_kmh': 80, 'speed_kmh': 50, 'warn_margin_kmh': 3, 'brake_margin_kmh': 10}, {'permitted': 80, 'action': 'none'})]]
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: stop target inside the margin | {'action': 'warning', 'permitted': 0} | {'action': 'warning', 'permitted': 0} | Passed |
| sampled regression 4 | {'action': 'brake', 'permitted': 45} | {'action': 'brake', 'permitted': 45} | Passed |
| boundary: target speed release | {'action': 'none', 'permitted': 40} | {'action': 'none', 'permitted': 40} | Passed |
| regression: curve below line speed | {'action': 'none', 'permitted': 99} | {'action': 'none', 'permitted': 99} | Passed |
| boundary: curve above line speed | {'action': 'brake', 'permitted': 120} | {'action': 'brake', 'permitted': 120} | Passed |
| control 1 | {'action': 'brake', 'permitted': 0} | {'action': 'brake', 'permitted': 0} | Passed |
| control 7 | {'action': 'none', 'permitted': 160} | {'action': 'none', 'permitted': 160} | Passed |
| sampled regression 10 | {'action': 'warning', 'permitted': 27} | {'action': 'warning', 'permitted': 27} | Passed |
SHA-256 / 78fa50aa1f9c009447031f2baa8719245de8de8fff91bb36ea76ea9e184ef470
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 2026-09-29T14:47:49.401244+00:00.
Case digest / 63e7bbc40e198c6af7cec2b8a65751a28519711186eeeb0df58fe1e1686f041e