Crocodile

Le Crocodile (Répétition des Signaux)

Steel track ramp sending electrical pulses to locomotive cab brushes for audible signal repetition and driver vigilance.

Driving Difficulty Level 2 / 5

Easy

Based on vigilance required, reaction window, and braking penalty severity.

menu_book System Overview

The Crocodile is one of the most famous and long-lived railway safety systems in Europe. Invented in 1872 for the French Chemins de Fer du Nord and later adopted throughout France, Belgium, and Luxembourg, it earns its nickname from the corrugated metal ramp placed between the rails resembling a crocodile's back. When a train passes, a flexible wire brush under the locomotive makes electrical contact with the ramp, sounding an in-cab chime on green or an alarm horn on restrictive signals.

settings How It Operates

check_circle A brass-and-steel contact ramp (the crocodile) is fixed in the center of the track roughly 100-200 meters ahead of signals.
check_circle At Clear signals (Green), a negative electrical tension is applied to the ramp, ringing a clear bell tone inside the cab with no driver action required.
check_circle At Caution or Restrictive signals (Yellow, Warning, Double Yellow), a positive electrical tension is applied, triggering a continuous horn or siren.
check_circle The driver must press the Vigilance button (Bouton de vigilance / Acquittement) within 4 seconds of crossing the ramp.
check_circle Failing to press the vigilance acknowledgment in time triggers automatic emergency service braking and marks a penalty onto the train recorder disk.

visibility In-Cab Visual & Audio Indications

notifications Warning Siren / Klaxon

Continuous buzzer or compressed air horn sounding at restrictive signals.

notifications Clear Bell Tone

A pleasant single bell ding confirming signal is green.

notifications Flaman Speed Recorder

Draws a mechanical blip on the paper tachograph chart verifying timely acknowledgment.

lightbulb Driver Tips to Avoid Penalty Brakes

verified On classic French routes, look out for the distinctive ridged metal ramp between the sleepers before signals.
verified Modern SNCF rolling stock pairs the Crocodile with KVB balises: the Crocodile provides the acoustic signal repetition while KVB checks the speed curve.

route Compatible Routes

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No specific routes mapped yet for this system in the database.