Crocodile (train protection system)

When Crocodile is a 1872 imported in northern France train control system. It is now regarded as very uncertain and supplemented by other systems, eg, KVB. The device is now used in France, Luxembourg and Belgium, but is to be replaced in the long term by ETCS equipment. In Belgium and Luxembourg it is used under the name Memor.

Due to the railway accident in Buizingen works hard on the equipment of the network with the TBL1 system, which should provide more security by 2015.

Operation

A Crocodile is usually on all signals with Vorsignalfunktion (ie pure distant signals, combined Haupt-/Vorsignalen and Disque ) attached. Likewise, several low-speed signals with Crocodile equipped. If it happens of a locomotive on the passing of a distant signal in warning position sounds in the cab of a horn. The driver has 5 seconds time to acknowledge the influence, otherwise an emergency brake is triggered. Another braking curve is not monitored, so the system only checks whether the driver has the signal perceived.

• ( Expect danger, slow travel expected ) to distant signals in warning position and at slow speed signals located on the Crocodile, a voltage of 20 V, which is horn to acknowledge as described above. Later, a yellow light was supplemented, the lights after the acknowledgment until the next signal and to remind the drivers to the distant signal in warning position. This was further developed in Belgium, the gong - fluit - systeem to Memor (of memorizing ). 154 vehicles ( corresponding to 11 %) of Infrabel and NMBS / SNCB possessed February 2010 not yet Memor, but only the older gong fluit - systeem that does not remind the drivers to drive past a distant signal in warning position.
• On main signals to the driving position (travel, slow travel ) lies on the Crocodile to a voltage of 20V. On newer vehicles, a gong and a blue lamp will light.
• At STOP field- Hauptsginalen no voltage is present at the Crocodile. It is assumed that in case of inadmissible passing the STOP field-side signal the absence of Gong shock as he sounds displayed on the passing of drive signals will be omitted and the engineer rated this correctly.

Construction

Between the rails is a steel bridge - the Crocodile - attached. If the Disque visible ( expect stop ), located on the Crocodile to a voltage of 20 V with respect to ground and the rails. On the traction unit, a brush is mounted, which transmits the power to the receiving device. The system was introduced at the time of steam locomotives and has mechanically activates a pipe that had to be reset by the driver. The function of the emergency brake was added later. On the tachograph both the influence, as well as the acknowledgment was noted by vertical bars. In order to analyze tachograph was better, later applying a voltage of -20 V when the signal showed a proceed aspect, that was signally insignificant. This tension did not affect the old receivers, but is documented on the tachograph.

Cab facility

In an influence the horn and a yellow light will flash. If the interference confirmed the yellow light until the next main signal.

Memor II

After three tragic accidents in Luxembourg (1997), the system was there added to Memor II . Memor II examines a braking curve, so that 800 m of influence a speed of 60 km / h must be achieved, otherwise an emergency brake application is initiated. The problem is still the lack of emergency brake at stop zeigendem main signal. Therefore, be placed behind each other at Memor II Two Crocodiles in more than 11 meters distance to a main signal. Do these two Crocodiles at the same time a positive potential with appropriate vehicle equipment, emergency braking is initiated.

The upgrade of the network was completed in Luxembourg in 2004 and 2017 to be replaced by an ETCS -based system.