Basic meaningStop
Stop before the signal. This flashing-red form is used by Entry Main Signals and Block Signals.
Light signals · Main signals
Main signals
The stop and proceed indications that control entry to a route, movement through a station and entry to the next block section.
Signal catalogue
Stop and
proceed aspects
Basic meaningStop
Stop before the signal. This steady-red form is used by Exit and Inner Main Signals.
Basic meaningProceed at reduced speed
Permission to pass with the reduced speed that applies to the route ahead.
Basic meaningProceed
Permission to pass at the highest speed allowed for the train and that part of the railway.
Physical lamp order
Two or three
main-signal lamps
Upper red · lower green
Signal 21 is shown by the lower green lamp. This head cannot show signal 22 because it has only one green position.
Green · red · green
The three fixed positions allow the signal head to show the applicable stop form, signal 21 or signal 22.
Authentic field reference
Block signal
B 218 YGR
Identification
Four main-
signal types
Identification plates and reflective mast bands help distinguish the four main-signal types.
Before a station
Entry Main Signal
Rectangular identification plate. Two yellow reflective mast bands are visible from both sides. It can show signal 20A and the applicable proceed indications.
From a station to the line
Exit Main Signal
Rectangular identification plate. It governs the route from a train track towards the line and uses signal 20B for stop.
Inside a station
Inner Main Signal
Rectangular identification plate. In an entry route, its two yellow reflective bands are visible from the front.
Between block sections
Block Signal
Round identification plate and two yellow reflective mast bands. It shows signal 20A or 22, never signal 21.
Route securing and interlocking
Before the signal
can show proceed
The sequence shows a route request, route check and securing, signal 22, then automatic return to stop at the first axle.
Route requested
The train approaches the Entry Main Signal. The Block Signal behind the train and the Entry Main Signal show stop.
Route checked and secured
The route beyond the Entry Main Signal is checked. The required points are correctly set and secured; the signal still shows stop.
Signal 22: Proceed
Once the conditions are satisfied, the Entry Main Signal may show two steady green lights.
First axle passes
The Entry Main Signal returns to stop as the first axle passes the detection point. The route remains secured until the train has cleared it.