The Polish (PKP) railway signalling system provides a complex outlook of traffic situations, yet is quite easy to understand. Signals can be divided into following categories:
Semi-automatic is the most important type of signal on Polish railways. Its name reflects the fact that it switches to a red (stop) aspect automatically after a train has passed it but it must be switched back to clear by an explicit action from a signal box or dispatch centre. It is the typical signal in use at stations.
A semi-automatic signal can be recognized by its post which is painted with red and white strips. Dwarf versions have their boxes painted so.
A red (stop) aspect on a semi-automatic signal must not be passed.
As presented on this compact chart, semi-automatic signals can display both near and distant functions. Near signals either command a stop or impose a certain speed limit beginning at that signal. Distant signals tell the driver what to expect at the next signal, especially when braking is required.
Distant signal
Vmax
100km/h
60 or 40km/h
Stop
unspecified
Vmax
100km/h
60km/h
40km/h
Stop
Near signal
All permitted aspects on semi-automatic signals:
S1 stop
Proceed or speed reduction order:
S2 clear, proceed at Vmax S3 reduce speed to 100km/h S4 reduce speed to 60 or 40km/h S5 stop at next signal
Speed limit 100km/h:
S6 speed limit 100; will be Vmax after next signal S7 speed limit 100; will be 100 after next signal S8 speed limit 100; will be 60 or 40 after next signal S9 speed limit 100; will be stop at next signal
Speed limit 60km/h:
S10a speed limit 60km/h; will be Vmax after next signal S11a speed limit 60km/h; will be 100 after next signal S12a speed limit 60km/h; will be 60 or 40 after next signal S13a speed limit 60km/h; will be stop at next signal
Speed limit 40km/h:
S10 speed limit 40km/h; will be Vmax after next signal S11 speed limit 40km/h; will be 100 after next signal S12 speed limit 40km/h; will be 60 or 40 after next signal S13 speed limit 40km/h; will be stop at next signal
Other speeds
Since 2007 the Ie-1 code which regards signalling allows other speed limits. They are indicated by a number representing the speed in tens of km/h (e.g. 5 means 50km/h) which is lit only with a more restrictive signalling aspect, such that the displayed number relaxes the regular aspect:
a speed limit of 50km/h is indicated by a digit 5 with aspects S10—S13
speed limits of 70, 80, 90km/h are indicated by digits 7, 8, 9 with aspects S10a—S13a
speed limits of 120 or 130km/h are indicated by numbers 12 or 13 with aspects S6—S9
On distant signals and repeaters these other speeds are not displayed, therefore a more restrictive aspect is effectively announced.
Nameplates
Semi-automatic signals on a station are tagged with consecutive letters of Latin alphabet, or with a letter followed by a number representing the track number the signal is located on (if multiple signals use the same letter).
The nameplates also contain speed indication which appears as a superscript or a fraction. The numbers have following meaning:
1 this signal is followed by a switch with straight direction, Vmax is possible
2 this signal is followed by a switch with diverging direction of 40km/h
3 this signal is followed by a switch with diverging direction of 100km/h
4 this signal is followed by a switch with diverging direction of 60km/h
Therefore, a nameplate H 1/2 means a signal named H that aside from S1 will also display S2-S5 aspects for straight direction and S10-S13 for diverging direction. Whereas P3 2 means a signal named P3 that aside from S1 only displays S10-S13 aspects because it's followed only by diverging points.
There may also be a letter m which specifies that this signal also functions as a shunting signal (see below).
Subsidiary signal
Subsidiary Signal
Sz, the subsidiary signal (Pol. sygnał zastępczy) is a signal issued in case of malfunction.
The first picture presents a typical case where the dispatcher cannot change the signal from S1. The second picture presents a case where the signal is powered down. Third picture presents a special signal where only the Sz sign can be displayed. The train must stop and wait until Sz is issued.
Automatic signals
Automatic signals are used on lines equipped with automatic block signaling. Their colour language is the same as aspects S1-S5 of semi-automatic signals. The main difference regards the S1 (red) aspect – After stopping, it can be passed but the subsequent maximum speed is limited to 20km/h.
Automatic signals have their posts painted white (without red strips) to be easily distinguished from semi-automatic signals.
Automatic signals are numbered by their nearest kilometre post multiplied by 10, odd numbers on the down track and even numbers on the up track. Signals on the track opposite to typical traffic (usually on the left track as Polish railways operate on the right track by default) have the letter N appended to the resulting number. A set of bi-directional automatic signals located on the 324.09 km marker will therefore be numbered 3241 on the down track, 3240 on the up track, 3241N on the down track reverse, and 3240N on the up track reverse. In the case of multi-track arrangements with signals located close to each other on different lines, other letters may be affixed to the numbers to distinguish signals on different tracks.
Automatic signals:
2-state ABS:
S2 proceed S1 stop, train ahead
3-state ABS:
S2 proceed (>1 block free) S5 stop at next signal (1 block free) S1 stop, train ahead
4-state ABS:
S2 proceed (>2 blocks free) S3 proceed (2 blocks free) S5 stop at next signal (1 block free) S1 stop, train ahead
other:
S1a is a special-case aspect, which forbids passing a signal displaying it, just like S1 on semi-automatic signals. It is used for safety reasons, for example, to forbid entering a tunnel during fire alarm. Other aspects are displayed normally, as in 3- or 4- state ABS.
(Unlit – no aspect displayed) — on a track with bidirectional ABS, only the signals for currently set direction of travel will be illuminated; signals for "the opposite direction" will not be lit. A driver who finds himself approaching an unlit signal must stop the train and alert the dispatcher.
Distant-only signals
Distant-only signal sign
Distant-only signal (Pol. tarcza ostrzegawcza literally meaning warning shield) is used on lines not equipped with ABS and lines with 2-state ABS. These signals are usually placed at braking distance from the next signal. The aspects they display are the same as signal aspects S2-S5, making them technically a signal which is just incapable of displaying a S1 (stop) aspect, however its aspects are not enforced.
Their posts are painted grey and equipped with a distant-only signal sign.
These signals are numbered with 'To' preceding the name of the signal it precedes, i.e. ToB will be the distant signal to B.
Distant-only signals:
Os1there will be stop at the (next) signal
precedes S1, Sz
Os2there will be proceed with Vmax at the (next) signal
precedes a signal with no speed restriction on its near signal: S2, S3, S4, S5
Os3there will be speed reduction to 100km/h at the signal
precedes a signal with a speed restriction of 100km/h on its near signal: S6, S7, S8, S9
Os4there will be speed reduction to 40 or 60km/h at the signal
precedes a signal with speed restriction of either 40 or 60km/h on its near signal: S10a, S11a, S12a, S13a (60km/h); S10, S11, S12, S13 (40km/h)
Repeater signals
When a signal aspect is not visible from the proper distance (because of track curves for instance), a repeater signal is installed to aid drivers. Up to three repeaters may be installed if needed. A repeater signal is not a substitute for a distant-only signal.
Their posts are painted grey and equipped with plates with Roman numerals: III, II, I where the "I" stands closest to the main signal. Their colour language is identical to warning shields, except the fact they also have a continuously glowing white light, which informs that this is not a main signal but a repeater.
These signals are numbered with the Roman numeral, 'Sp', and the number of the signal it repeats. For example, the second repeater ahead of a signal G will be called IISpG.
Repeater signal:
Sp1 there will be S1 (stop) at the signal
Sp2 there will be proceed with Vmax at the signal
Sp3 there will be speed reduction to 100km/h at the signal
Sp4 there will be speed reduction to 40 or 60km/h at the signal
The following table presents as an example, a station-entry signal designated "B" displaying the aspect S13 (speed limit 40km/h, stop at the next signal) preceded with distant-only signal and three repeaters:
distant-only signal
3rd repeater
2nd repeater
1st repeater
the main signal
ToB
3SpB
2SpB
1SpB
B
braking distance
visibility distance
Level crossing warning
Level crossing warning is placed in a braking distance before an automatic level crossing. The signal tells the driver whether automobile drivers are warned about an approaching train (blinking red lights, barriers). Normally, level crossing warning signals display no aspect (i.e. are unlit). They light up in the front of an approaching train which is the first clue that the system is working correctly.
Level crossing warning signals are unrelated to other signals, therefore in case of Osp1 signal a train must proceed at 20km/h regardless the higher speed allowed by last signal.
Their posts are painted black and white strips. They are numbered by the kilometre location of the level crossing they refer to, multiplied by 10 – other than the milepost reference difference, their numbering functions like that of automatic block signals.
Level crossing warning signals
Osp1 Automatic level crossing is not working properly. The front of the train must pass the crossing with its speed limited to 20km/h and be prepared for an immediate stop.
Osp2 Automatic level crossing operating properly. Proceed at normal speed.
Shunting signals
Shunting signals (Pol. tarcza manewrowa literally manoeuver shield) are used exclusively at stations. A consist shunting on such signals must not leave the station. Shunting signals are either stand-alone or incorporated into semi-automatic signals, which include the letter "m" in their name on such occasions.
Stand-alone shunting signals have their posts painted gray, except in the case it is a part of the semi-automatic signal, which is painted with white-red stripes. Stand-alone shunting signals are numbered with 'Tm' preceding an Arabic number, and are numbered independently of other signalling or points within a station, e.g. Tm7.
Shunting signals:
Ms1 shunting forbidden S1 stop and shunting forbidden
Ms2 shunting allowed
Old colour light signals
The colour light signals installed between 1959 and 1969 differ from the contemporary system. They are still in use at several stations. As a matter of fact they can also be used with ETCS Level 1, only the LEU unit must be reprogrammed to understand certain combinations of lights differently.
Semi-automatic signal configuration:
old
new
The old system did not use blinking lights, except the subsidiary signal, but that one was not popular at that times.
The pictures to the left present old and contemporary configuration with indication which colour chambers may blink if required.
There is a principle, observed then and now that two chambers of the same colour must be separated by a chamber of other colour.
Old and contemporary aspects of semi-automatic signal
old
description
contemporary
S1 stop
the same expression
S1
S4 proceed at Vmax
the same expression
S2
no equivalent for contemporary S3
S6 reduce speed to 40km/h
different expression
S4
S2 stop at next signal
the same expression
S5
no equivalent for contemporary S6-S9, S10a-S13a, S11
S5 proceed at 40km/h
different expression
S10
S12
S3 proceed at 40km/h, stop at next signal
the same expression
S13
Old distant signals and repeaters
distant signal
repeater
With distant signals there is a principle that the chambers illuminating together, although of different colours, cannot be adjacent to each other. This explains why there are two chambers of orange colour next to each other.
With repeaters this principle is apparently not observed.
Old and contemporary aspects of distant signals and repeaters
old
description
contemporary
Ot1/Sp1 there will be stop at the signal
the same expression
Ot2/Sp2 there will be proceed at Vmax at the signal
the same expression (Flipped on repeater singal)
Ot3/Sp3 reduce speed to 40km/h, there will be proceed at 40km/h at the signal
A railway signal is a visual display device that conveys instructions or provides warning of instructions regarding the driver's authority to proceed. The driver interprets the signal's indication and acts accordingly. Typically, a signal might inform the driver of the speed at which the train may safely proceed or it may instruct the driver to stop.
Railway signalling (BE), or railroad signaling (AE), is a system used to control the movement of railway traffic. Trains move on fixed rails, making them uniquely susceptible to collision. This susceptibility is exacerbated by the enormous weight and inertia of a train, which makes it difficult to quickly stop when encountering an obstacle. In the UK, the Regulation of Railways Act 1889 introduced a series of requirements on matters such as the implementation of interlocked block signalling and other safety measures as a direct result of the Armagh rail disaster in that year.
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