Swedish railway signalling

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.

Main signals

The main signals (huvudsignaler) display the following aspects:

Signal		Meaning	Comment
	Stop	The signal must not be passed without permission from the traffic control.[1] During shunting operations permission to pass a home signal displaying stop may be given with a radio or with a dwarf signal.[2]	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 40 km/h (25 mph).
	Proceed 80	Authorises the driver to pass the signal at 80 km/h (50 mph) or at a higher speed given by the ATC system.[3]	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 40 km/h (25 mph) or at a higher speed given by the ATC system. The next signal might be displaying stop if it is farther away than 450 metres (1,480 ft), so the driver must approach the next signal cautiously and be prepared to stop short of it.[3]
	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. [3] Block signals on the Iron Ore Line between Peuravaara (near Kiruna) and the Norwegian border can show Proceed 80, expect stop with only one flashing green light (right image).[4][5]	The next signal is between 800 and 3,000 metres (2,600 and 9,800 ft) away.[2] 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.[2]
	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 40 km/h (25 mph) or the speed shown on the ATC driver's display.[3]
	Proceed 40, short route	Authorises the driver to pass the signal at a maximum speed of 40 km/h (25 mph). The next signal is showing "stop" and is closer than 450 metres.[3]	The next signal could also be a stop light at the end of the line, or an End Board (S-tavla).[3]

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. The speed limits apply to trains without Automatic Train Control (ATC) equipment. ATC signalling typically allow higher speeds.

Two light signalling (Malmö and Stockholm city tunnels)

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 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.[6]
	Clear 40 expect clear 40	Authorises the driver to pass the signal at 40 km/h (25 mph) or at a higher speed given by the ATC or ERTMS system. The next signal is displaying a proceed 40 aspect.[6]
	Clear 40 caution	Authorises the driver to pass the signal at 40 km/h (25 mph) or at a higher speed given by the ATC or ERTMS system. The next signal is showing "stop"[6] and is closer than 450 metres (1,480 ft).

These signals should not be confused with normal main signals with two lights. They have yellow number signs, while the "Two light signals" shown here have blue ones.[6]

Distant signals

Distant signals (försignaler) are informational signals used to give an advance warning about the next home signal. Distant signal are typically located 800 to 1,200 metres (2,600 to 3,900 ft) in advance of the home signal in question.[7]
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.[8]
	Expect Proceed 80	The next signal is displaying Proceed 80.[8]
	Expect Proceed 40	The next signal is displaying proceed 40,[8] so the driver must decrease speed and approach the next signal prepared to pass it at a speed not exceeding 40 km/h (25 mph) 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

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.[9]
	Movement allowed	Shunting allowed. Points and derailers are in the right position. The track is free.[9]
	Movement allowed Track not clear	Shunting allowed Points and derailers are in the right position. The track is not free, or caution is needed.[9]
	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.[9]

A huvuddvärgsignal at Stockholm Central Station displaying "stop"

There are also types of dwarf signals, called "Main Dwarf signals" (Huvuddvärgsignal) used as stand-ins for home signals in stations with lot of shunting or where there are a lot of switches that needs a signal. In addition to the dwarf signal aspects given above, these signals also have a red light and two green ones (one for "proceed 40", the other for "proceed 80").[10]

Road crossing signals

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.[11]
	Pass (Crossing clear)	The road crossing is secured.[11]

The same aspects are also used at moveable bridges, but with another sign under the signal.[12]

Distant road crossing signal

Some road crossing signals have a distant signal (Vägkorsningsförsignal (V-försignal)), placed at a distance (usually not breaking 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.[13]
	Expect Pass (Crossing clear)	The road crossing is secured.[13]

The distant road crossing signal is nicknamed "skull" (döskalle).

Fail safe

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 Danish railway signalling 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.

References

• Trafikverkets trafikbestämmelser för järnväg (TTJ) Modul 3H: Signaler - System H (PDF) (in Swedish). Swedish Transport Administration (Trafikverket). 1 June 2017. Retrieved 3 November 2018.
• Swedish signalling section of The Signal Page (TSP)
• Signalfakta by Per Forsström (in Swedish) at the Wayback Machine (archived 27 May 2007)

Notes

1. Trafikverket 2017, p. 17.
2. Trafikverket 2017, p. 19.
3. Trafikverket 2017, p. 18.
4. Trafikverket 2017, p. 118.
5. "Allmänna riktlinjer" (PDF). Bodens linjebok (in Swedish). Swedish Transport Administration. 30 July 2018. p. F1. Retrieved 4 November 2018.
6. Trafikverket 2017, p. 113.
7. Trafikverket 2017, p. 25.
8. Trafikverket 2017, p. 26.
9. Trafikverket 2017, p. 34.
10. Trafikverket 2017, pp. 22–23.
11. Trafikverket 2017, p. 52.
12. Trafikverket 2017, p. 58.
13. Trafikverket 2017, p. 53.