It is a security system much like the ATP, or for example the PZB.
Next will follow a description of the system. This is to add to the wish-list for Zusi3 in hopes Carsten may consider it's development.
On the lines equipped with color light signaling (TCB), usually the Convel system is installed. The portuguese ATP system is suplied by ADtranz (ex-Ericsson) and it is a point-based information system, that is, the system only receives the signal information from the track placed beacons when passes over them. This system fully ensures that trains run within speed limits, considering their braking power, either due to permanenent speed restrictions (temporary speed restriction can also be controlled but usually the aren't) and the signal indications. Certain aditional functions can also be monitored by the system, as main switches commands of electrical units over neutral zones, ETH command over signalling sensitive areas.
Closed signal approaches are usually monitored at a maximum 24 km/h in the last 50/100 meters but whenever required it will provide signal approaches at the speed of 13 km/h, if 120 meters of flank protection are provided beyond the closed signal.
The system allows the driver to overtake signals in whenever required, ãccording to strict procedures. The system will monitor 30 or 15 km/h beyond the closed signal, depending if the train approached the signal with the 120 meters of skiding protection or not
And many other features wich make this system extrenely safe.
the in-cab panel
also see: http://images.fotopic.net/11a9bf.jpg
Functions on the main panel:
1-Shunting key - it should be pressed when you on shunting movement. It allows a single movement of 500 meters in either direction at the maximum speed of 25 km/h (further 500 meters can be obtained by pressing the key and if this isn't done before the 480 meters the system will request the driver to do it otherwise and emergency braking occurs)
2-Auxiliary Display - Basicly it is the "warning" display. no need for action yet. Usualy shows the next speed limitation.
3-Red Led - System error(internal error) - it might or not force the driver to put the system out of service, in either case the system will command an emergency braking and it has to be shut down and reinitializated
Yellow led - Beacon error - when the system is not able to read properly a beacon on the track it forces the train down to 30 km/h until the next color light signal and it flashes the led
Green Led - Over speeding - when the train passes in 5 km/h the speed limit, this led lights up and an audible warning is heard. When you over speed over 10 km/h above the speed limit another audible warning can be heard: the air flowing out of the general conduct!!!!!!(that is: braking) the system will allow the driver to release the brakes as soon as the speed is within the limits
4-Main Display - This is the "execute" display. It indicates the maximum speed allowed or that you must start braking due to a lower speed limit.
5-Brake release key - If Convel aplies the brake, it will lit the led over this button in a fixed manner. When the Convel allows the driver to take control over the brakes again, the led will flash, having the driver to press the button so that the brakes are released.
6-Speed restriction void key - Certain speed restriction are not totally supervised, leaving to the driver the task of telling convel when the speed restriction is over. When the train enter into a "partially controlled" speed restriction the led will it at the begining of it, having the driver to press the key, when the head of the train passes at the signal wich marks the end of the speed restriction. The system will then control the length of the train before realeasing the speed. This key is also used at the begging of a run in a non-equipped area. Convel, when it has no information, only allows a train to run at 30 km/h, but after 100 meters without finding beacons it will allow the driver to release the speed by pressing this button(the driver must only do this if the track has no Convel installed)
7-Closed signal overtaking key - The name says it all.
8-This regulators are used to control the volume and the luminosity of the displays.
9-Data introduction key -It is used to confirm the data introduced in "10" and as a test key for the leds and audible warnings
10-Data introduction Section - This is were the maximum speed, length, brake reaction time, acceleration of braking and the train type are introduced.
11-Minor error led - it lits when there is an error in the wheels diameter configuration
to see more about portuguese regulations and signaling see: http://hjcl.xico.co.uk/
