The signalling system used on the standard-gauge railway network in Sweden is based on that of the traditional mechanical semaphore signals. Currently only colour-light signals are used, together with the Ansaldo L10000 Automatic Train Control system.
The main signals (huvudsignaler) display the following aspects:
| Signal | Meaning | Comment | ||
|---|---|---|---|---|
| Stop | The signal must not be passed without permission from the traffic control. During shunting operations permission to pass a home signal displaying stop may be given with a radio or with a dwarf signal. | Permission to pass a red signal is given during signal system faults and must be documented by both driver and traffic control, and the max speed is then 40km/h. | ||
| Proceed 80 | Authorises the driver to pass the signal at 80km/h or at a higher speed given by the ATC system. Signs can give a lower or (if no ATC) higher speed. | The signal changes to red when the train passes the track circuit limit a few metres in front of the signal, so passengers might see the signal showing red. | ||
| Proceed 40, caution | Authorises the driver to pass the signal at 40km/h or at a higher speed given by the ATC system. The next signal might be displaying stop if it is farther away than, so the driver must approach the next signal cautiously and be prepared to stop short of it. | |||
| Proceed 80, expect stop | Authorises the driver to pass the signal at 80 km/h or at a higher speed given by the ATC system. The next signal is displaying stop, so the driver must decrease speed and approach the next signal prepared to stop short of it. Block signals on the Iron Ore Line between (near Kiruna) and the Norwegian border can show Proceed 80, expect stop with only one flashing green light (right image).[1] | The next signal is between 800and away. If the distance to the next signal is more than 3,000 metres, a separate free-standing distant signal is used to govern the approach to that signal. | ||
| Proceed 80, expect proceed 80 | Authorises the driver to pass the signal at 80 km/h or at a higher speed given by the ATC system. The next signal is displaying a proceed 80 aspect. | |||
| Proceed 80, expect proceed 40 | Authorises the driver to pass the signal at 80 km/h or at a higher speed given by the ATC system. The next signal is displaying proceed 40, so the driver must decrease speed and approach the next signal prepared to pass it at a speed not exceeding 40km/h or the speed shown on the ATC driver's display. | |||
| Proceed 40, short route | Authorises the driver to pass the signal at a maximum speed of 40km/h. The next signal is showing "stop" and is closer than 450 metres. | The next signal could also be a stop light at the end of the line, or an End Board (S-tavla). | ||
The aspects may seem a little inverted, since a single green light means proceed 80, two green lights Proceed 40, caution and three green lights stands for Proceed 40, short route. In other words: more green means more cautiously. Some other countries e.g. Norway have opposite. If there is a sign saying lower speed limit than 80, of course that is valid. The speed limits apply to trains without Automatic Train Control (ATC) equipment. ATC signalling typically allow higher speeds, up to 200km/h. If there is no ATC, signs can show higher speed, but rarely above 110 km/h. If there is ATC there can be even higher signs which are valid only with ATC.
On some urban lines, such as the City Tunnel in Malmö and the Stockholm City Line, a simpler signal system is in use until ERTMS is fully implemented. The interpretation of the signals follow the ERTMS level 1 standard, but the actual look is national.
This system uses two light signals with blue number signs (instead of yellow/white in normal signalling) and can show the following aspects:
| Signal | Meaning | ||
|---|---|---|---|
| Stop | The signal must not be passed without permission from the traffic control. During shunting operations permission to pass a home signal displaying stop may be given with a radio or with a dwarf signal. | ||
| Proceed 40 expect proceed 40 | Authorises the driver to pass the signal at 40km/h or at a higher speed given by the ATC or ERTMS system. The next signal is displaying a proceed 40 or proceed 40 caution aspect. | ||
| Proceed 40 caution | Authorises the driver to pass the signal at 40km/h or at a higher speed given by the ATC or ERTMS system. The next signal is showing "stop" and is closer than . | ||
These signals should not be confused with normal main signals with two lights, which have yellow number signs, while the "Two light signals" shown here have blue ones. The meaning is different to normal meanings of the signals, but if combined with a speed limit 40 (not valid for ATC) sign, the meanings are essentially the same.
Distant signals (försignaler) are informational signals used to give an advance warning about the next home signal. Distant signal are typically located 800to in advance of the home signal in question.
The aspects a free-standing distant signal can display are:
| Signal | Meaning | ||
|---|---|---|---|
| Expect stop | The next signal is displaying stop, so the driver must decrease speed and approach the next signal prepared to stop short of it. | ||
| Expect Proceed 80 | The next signal is displaying Proceed 80. | ||
| Expect Proceed 40 | The next signal is displaying proceed 40, so the driver must decrease speed and approach the next signal prepared to pass it at a speed not exceeding 40km/h or the speed shown on the ATC driver's display. | ||
The signal indication is the same as for the combined aspects in the main signals.
Dwarf signals (dvärgsignaler) are used as shunting signals and can show the following aspects:
| Signal | Meaning | ||
|---|---|---|---|
| Stop | The signal must not be passed without permission from the traffic control. | ||
| Movement allowed | Shunting allowed. Points and derailers are in the right position. The track is free. | ||
| Movement allowed Track not clear | Shunting allowed Points and derailers are in the right position. The track is not free, or caution is needed. | ||
| Movement allowed Check points and clearance | Shunting allowed The driver must manually check the position of points and derailers, and the track clearance. Points and derailers are often manual or put in shunting mode. | ||
Road crossing signals (Vägkorsningssignaler (V-signaler)) are used at road crossings. They tell the driver if the crossing is clear (lights flashing, bells ringing or, if available, gates are closed)They can show the following aspects
| Signal | Meaning | ||
|---|---|---|---|
| Stop before crossing (Crossing not clear) | The road crossing is not secured. The train must stop before the crossing if possible. | ||
| Pass (Crossing clear) | The road crossing is secured. | ||
The same aspects are also used at moveable bridges, but with another sign under the signal.
Some road crossing signals have a distant signal (Vägkorsningsförsignal (V-försignal)), placed at a distance (usually not braking distance) from the road crossing signal.
| Signal | Meaning | ||
|---|---|---|---|
| Expect Stop before crossing (Crossing not clear) | The road crossing is not secured. The train must stop before the crossing if possible. | ||
| Expect Pass (Crossing clear) | The road crossing is secured. | ||
The distant road crossing signal is nicknamed "skull" (dödskalle).
Because the aspects are in reverse with more green lights meaning slower the aspects are not fail safe, so lamp proving is needed to prevent lamp failure giving a faster aspect.
Single and Double Green signals work the other way with Norwegian railway signalling and and it would be unsafe for drivers to cross the border, unless ATP were fitted. It is not permitted for Swedish drivers to drive into Norway and opposite where there is no ATC, unless extra education is taken (and before ATC was introduced everywhere in the other country except for a few kilometers from the border where crew change stations were located). This meant that freight trains Oslo–Narvik passed Hallsberg southeast of Oslo until the shortcut Kil–Ställdalen was upgraded to ATC in 2017.
European Rail Traffic Management System(ERTMS/ETCS) has been introduced on a few railways in Sweden such as Botniabanan where it is actively being used. Mainly ERTMS level 2 is used, in which basically no light signals exist and all messages are shown on a display in the driver's compartment of the train.
Two railways, Citybanan and Citytunneln use signalling according to ERTMS level 1, although ATC is still used there, not ERTMS (for now).
An unauthorized stop signal passage (OSPA), ie the passage without permission of a signal or sign meaning stop (red main signal, horisontal dwarf signal, ERTMS arrow sign and more) is considered a serious incident. They are divided into three categories, A where the signal showed stop even before the process, which may be due to the driver, failure of the train brakes, slipping and more, category B, where the signal was inadvertently set to stop due to technical error or mistake of the signalman, and category C, where the signal was intentionally stopped, for example due to a sudden danger such as a car at a level crossing.[2] If it is suspected to be due to the driver, he may not drive any more until the investigation has been completed, and another driver may drive the train after an investigator has collected information about the train's route, usually causing a multiple hour delay. A driver who has caused several OSPAs permanently loses the license.