Polish railway signalling
Polish railway signalling system provides complex outlook of traffic situation, yet is quite easy to understand. Signals can be divided into following categories:
- near and distant displays — signals (semi-automatic, automatic)
- distant-only displays — warning shields
- auxiliary — semaphore repeaters
- shunting — maneuver shields
Most signals are electric. Mechanical signals are in decline.
Colour Light Signals
Semi-automatic signals
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 | ||||
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Vmax | 100 km/h | 60 or 40 km/h | Stop | unspecified |
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Vmax | 100 km/h | 60 km/h | 40 km/h | Stop |
Near signal |
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 20 km/h.
Automatic signals have their posts painted white (without red strips) to be easily distinguished from semi-automatic signals.
Warning shields
![](http://upload.wikimedia.org/wikipedia/commons/thumb/7/7b/W_1_Wska%C5%BAnik_usytuowania.svg/60px-W_1_Wska%C5%BAnik_usytuowania.svg.png)
Warning shield (Pol. tarcza ostrzegawcza) is distant-only signal display. It is used on lines not equipped with ABS. Placed in the braking distance to allow the driver to stop before the signal ahead. Their colour language is the same as signal aspects S2-S5, making them technically a signal which is just incapable of displaying a S1 (stop) aspect.
Their posts are painted grey and equipped with the warning shield sign.
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 warning shield.
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.
The following table presents as an example, a station-entry signal designated "B" displaying the aspect S13 (speed limit 40 km/h, stop at the next signal) preceded with warning shield and three repeaters:
warning shield | 3rd repeater | 2nd repeater | 1st repeater | the main signal | |
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ToB | 3SpB | 2SpB | 1SpB | B | |
braking distance | |||||
visibility distance |
Level crossing warning shields
Level crossing warning shield is placed in a braking distance before an automatic level crossing. The signal tells the driver whether automobile drivers are warned about an approching train (blinking red lights, barriers). Normally, level crossing warning shields display no signal (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 shield signals are unrelated to other signals, therefore in case of Osp1 signal a train must proceed at 20 km/h regardless the higher speed allowed by last signal.
Their posts are painted black and white strips.
Manoeuver shields - Shunting Signals
Manoeuver shield (Pol. tarcza manewrowa) is shunting signal, used exclusively at stations. A consist shunting on such signals must not leave the station. Manoeuver shields are either stand-alone or incorporated into semi-automatic signals, which bear letter "m" on such occasions.
Stand-alone manoeuver shields have their posts painted gray.
Manoeuver shields: | ||
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Ms1 shunting forbidden S1 stop and shunting forbidden |
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Ms2 shunting allowed |