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Veurs, picture 12.1
Jan Uyttebroeck

Basic of permissive signalling

A permissive signal protects the block after the signal till the next signal. In this block no obstacle can be found. A permissive signal is open in his default state. If the following block is cleared then the signal shows green. This works full automatically.

Permissive signals in the opposite direction always flash.

The identification plate of the permissive signal describes the track A or B, an X for the opposite direction and the hectometers. See picture 12.1


There are 2 kinds of permissive signals:

A1) The signal is full automatic. These permissive signals have on their pole a crown (see picture 12.1).
This crown will be important when the signal is disturb (red or no light). This crown will allow the train engineer to proceed with a restricted speed and without a writing permission.

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Picture 12.2
This signal stands at kilometer 25.9
Signal with crown that allows the train engineer to proceed with restricted speed when the signal is disturb

A2) The permissive signal protects a level crossing. In this case the automatic level crossing works in cooperation with the automatic signal and a malfuntion of the level crossing can force this signal to red. There is a white box with two red line (instead of the crown) mounted on the pole which contains a line layout with all the level crossings for this block. Only when the signal shows red, the trainengineer must take this paper and must fill in a form. He may proceed with restricted speed and must whistle at every level crossing.

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Picture 12.2
B track and contraflow
In the box, marked with the red lines, the train engineer can find the line layout of this block

But there are some extensions:

B1) A free block is indicated with a crown. But on some tracks (between Ath and Jurbise and between Gent and Zelzate) the signals only have a crown even when there are level crossings in the block.

B2) The intermitterende permissive signals: in most occasion they are placed in "permissive mode" and they work automatic. When the crown lamp is illuminated together with the red light, the trainengineer is allowed to proceed. He must act the same as mode A1.

B3) The signals at de noord zuid verbinding (NZV), the connections between Brussels North and the South station are seen as full automatic.They don't have a crown or light and after the train engineer has stopped at a unsecured signal he may proceed. These signals carry identification plate with 2 numbers without any letters.
I've heard that these signal are provided with a telephone box. If the signal is disturb and a lamp is lit on the telephonebox, the trainengineer must phone immediately to the control room.


Some permissive signals show green-yellow vertical in there default state.
Entry signal of station Diest out of the direction Hasselt. Entry signal of station Leuven out of the direction Kortenberg

Old configuration

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Signal showing green-yellow vertical at line 36 Winksele.
The signal dates back to 1972. The signal really leans to the left side. The crown is nearly recognisable

New congifuration

The layout has changed a litle bit due to TGV work, and has created a unique layout with two permissive limited approach signals


A permissive signal can be in combination with a distant signal. This signal is used less.

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Sometimes two train can be found in the same block.
An example: one train is waiting to be signaled to the opposite track. The next freight train is in the meantime approaching in the same direction. He will be stopped by the red permissive signal.

The train engineer may proceed with limited speed and he will end up on the tail.

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