Danish Signaling, early single track station with entry and exit signals

Contents

The Station Layout

The track layout shown below represents a typical station on a single track line. The station has a main track and a siding for meets, an industrial spur or a team track. The station in the example also has platforms for passenger services. Such stations often also feature one or more road crossings within the station area but for clarity these have been omitted.

Signal layout

The signal configuration shown in this document represents the early signal scheme for smaller stations with relay interlockings, as they were built in the 1950s on mainlines. The interlocking is an early example of the type 1954 relay interlocking. Compared to other similar stations it was relatively new to install Exit Signals as a standard. The station had no line block towards its neighboring stations and stations of the time were locally manned. Since the station had no facing point turnouts in the exit end, Exit Signals were not strictly necesssary, but in 1952 the railrays had decided that all stations on lines with line speed exceeding 75 km/h were to be equipped with Exit Signals. The station configuration shown below is valid for the most typical timeframe (ca. 1961-1975) and will be used as the general example in this document:

The station was equipped with Entry Signals with Speed Indicators, which was standard when resignaling lines with line speeds exceeding 75 km/h. Besides indicating the permitted entry speed, the Speed Indicator also was a prerequisite for showing "Stop and Proceed". The stations were also given 3-lamp Distant Signals, placed 800 m on approach to the Entry Signals.

As was common from the semaphore signal days the Exit Signals were placed side-by-side, usually at the tip of the exit turnout. The signals formed a Signal Group (Danish: Signalbillede), in which the position of the signal determined which signaled track it governed (left signal for the leftmost signaled track etc.). This arrangement allowed entering trains to pull forward all the way to the Exit Signal. However, by doing this they blocked the exit turnout and it was therefore implicitly expected that the train stopped before the turnout. Signs have later been installed that mark the latest point of stopping.

The signal scheme's development over the years is listed in a separate section below. Since the relatively few stations of this type had different lifecycles, Tistrup station has been chosen as a representative of the development over time. Not least because it is the only such station left and therefore has gone though the most changes over the years.

Signals and signs used

The signals and signs shown above are explained in the table below:

	Abbr.	Signal type	Danish name	Purpose
	F	Distant Signal	Fremskudt signal	These stations were built on lines with line speeds above 75 km/h, making distant signals mandatory. The distant signals are the 3-lamp type and placed 800 m on approach to the entry signal.
	I	Entry Signal	Indkørselssignal	Entry signals were 4-lamp signals with speed indicators. At the time of construction this was the standard signal on other than branchlines. The station interlockings were constructed before 1961 and thus originally featured the same signal aspects as the semaphore signals, i.e. with red on top (as shown to the left). In the 1961 signal rules change the signals were changed into the present day configuration, shown to the right. This modification was part of a country-wide change in signal aspects and indications.
	Ubt	Station Unmanned	Stationen Ubetjent	The Station Unmanned Signal was used to indicate that the station was unmanned and that the trains could depart without a departure signal from the signaler. The signal became obsolete in 1975 on stations equipped with Exit Signals, as a clear Exit Signal alone was now sufficient for departure. The Unmanned function was removed from the interlocking when the station was converted to CTC ca. 1995.
	Und	Hand signal "Message to be delivered"	"Underretning følger"	Hand signal given by the signaler in certain situations when the train was to be handed a message. The train must slow down to to receive the message and stop if it does not receive the message.
	Afg	Hand signal "Depart"	Håndsignal "Afgang"	Departure signal (hand signal), given by the signaler.
	U	Exit Signal	Udkørselssignal	Exit signals were 2-lamp signals as found on most single track stations. There was a signal per track (main+siding) in each direction. As per tradition from semaphore signals the signals were located side-by-side, usually by the tip of the exit turnout. They formed a so called "Signal Group" (Danish: Signalbillede), in which the signal's position within the group determined which track it governed (e.g. leftmost signal for leftmost track).
	SfU	"Stop for Exit Signal" sign	"Stop for U-signal"-mærke	When introducing "ATC Trainstop" (Danish: ATC Togstop", simplified ATC system) around 2005 it became necessary to explicitly mark the end of the route as being the end of the platform tracks. "Stop for Exit Signal" signs were placed at the end of the platform track thus forbidding arriving trains to pass the fouling point of the exit turnout. The practice of which was already long gone.
	Rg	Limit of Shunting Sign	Rangergrænsemærke	Marks the limits of how far towards the open line any shunting inside the station can go. Beyond this point line block systems on the open line may be affected and/or the safety overlap of a train approaching the Entry Signal from the open line may be compromised. The Limit of Shunting sign is typically located some 150 m inside the Entry Signal.

Changes over time

The changes listed in the table above made the station layout change as shown below:

Time frame	Station layout	Remarks
- 1961		The stations were built with the original Entry Signal lamp configuration. Distant Signal aspects did not reflect the permitted entry speed. Latest operational stopping location for incoming trains was not marked.
1961 - 1975		Ca. 1961 the Entry Signals were modified to the current lamp configuration and current signal aspects. Distant Signals now only gave permissive indication for "High" (75 km/h or higher) entry speed. This modification was part of a country-wide change in signal aspects and indications.
1975 - 1995		In 1975 the new signal rulebook "SR75" meant that the "Station Unmanned" signal no longer was needed on unmanned stations featuring Exit Signals. The signal was removed.
1995 - 2005		Ca. 1995 the station was converted to CTC, for which a line block system was established towards the neighboring stations. Even though this must by far have been the largest modification to the interlocker over its lifespan, it had little to show on the outside (though some signals would drop to "Stop" earlier when trains passed). Signals and signs were not changed. The "Halt" and "Unmanned" functions were removed from the interlocking.
2005 -		Sometime around year 2005 "Stop for Exit Signal" signs were erected in order to explicitly mark the latest stopping location. In Tistrup the change was dictated by the intruction of the "ATC Trainstop" (Danish: ATC Togstop" simplified ATC system, but a country-wide change of signage, in situations where the actual End-of-Route was earlier than the physical signal location, was initiated.

Signal functions after 1961

Distant and Entry Signal aspects and indications were changed system-wide ca. 1961. The time after 1961 thus represents the signaling thorughout the main lifespan of the station. The pre-1961 signaling is shown in a separate chapter below.

As mentioned previously the Station Unmanned signal was removed in 1975 and "Stop for Exit Signal" Signs introduced in 2005. This, however, did not affect signal aspects and unless noted only pre-1995 examples are illustrated in the examples below.

Entry Routes

An Entry Route (Danish: Indkørselstogvej) is a locked route from the station Entry Signal to the train's Stopping Location (Danish: Standsningsstedet), plus a Safety Overlap (Danish: Sikkerhedsafstand) beyond it. The latest Stopping Location was originally not marked, but was implicit (stop before fouling the exit turnout). The secured track beyond the Stopping Location, towards the open line, is to be considered the Safety Overlap.

Entry Route (Danish: Indkørselstogvej) to the Main Track. The Entry Signal displays "Proceed (at high speed)" (Danish: "Kør (med høj hastighed)"), i.e. enter the station at line speed but prepare to stop at the station. "Proceed (at high speed)" is only used where the permitted speed is at least 75 km/h, i.e. line speed. Distant Signal shows "Main Signal shows Proceed" (Danish: "Hovedsignalet viser Kør").
To illustrate the later addition of markers for Stopping Location, the same Entry Route is shown with the contemporary "Stop for Exit Signal" signs. The exit turnout is now considered part of the safety overlap rather than the route itself.
Entry Route to the siding. The Entry Signal displays "Proceed at reduced speed" (Danish: "Kør med begrænset hastighed"). The exact permitted speed is indicated by the Speed Indicator (Danish: Hastighedsviser), in this case Medium Speed (50 km/h, later raised to 60 km/h). The Distant Signal shows "Caution" (Danish: "Kør Forsigtigt").
Degraded signaling, failure preventing "Proceed". The Entry Signal can be switched to the "Stop and Proceed" (Danish: "Stop og Ryk Frem") aspect in case of certain failures. Such failure could be a faulty track circuit or a failing green lamp in the Entry Signal. The "Stop and Proceed" aspect is the same for either Entry Route. The Distant Signal shows "Caution" (Danish: "Kør Forsigtigt").

Exit Routes

An Exit Route (Danish: Udkørselstogvej) is a locked route from the front of the train to the Station Limits (i.e. the opposing Entry Signal). In practical terms the Exit Route starts at the end of the platform track and covers the turnout in the exit end of the station. The Exit Signals for both tracks are located side-by-side forming a Signal Group (Danish: Signalbillede). The position of the signal within the Signal Group determines which track it is valid for (the rightmost signal is valid for the rightmost track etc.).

Exit Route from Main Track. The righthand Exit Signal (valid for the Main Track) shows "Proceed" (Danish: "Kør"). The signaler's departure signal was only required until 1975.
To illustrate the later addition of markers for Stopping Location, the same Exit Route is shown with the "Stop for Exit Signal" signs.
Exit Route from Siding. The lefthand Exit Signal (valid for the Siding) shows "Proceed" (Danish: "Kør"). The signaler's departure signal was only required until 1975.

Combined Entry and Exit Routes

An Entry Route extended with an Exit route forms a Combined Route (Danish: Sammensat togvej). A Combined Route through the Main Track forms a Through Route (in lack of a better term for the Danish term: Gennemkørselstogvej). A Through Route is the only Combined Route that allows the Entry Signal to show the "Extended Proceed" aspect (Danish: Kør Igennem).

Early rules prescribed the Signaler to - if possible - clear the signals in sequence towards the train, i.e. the Exit Route before the Entry Route. Generally the interlockings allowed (and allows) either route through the Main Track to be set first, but on stations with road crossings in their exit end, the sequence will determine if road crossings in the station area will be activated early (expecting the train to proceed without stopping at the station) or delayed (for trains stopping at the station).

Through route. Exit Signal shows "Clear", Entry Signal shows "Extended Proceed (at high speed)" (Danish: "Kør Igennem (med høj hastighed)") and Distant Signal shows "Main Signal shows Extended Proceed" (Danish: "Hovedsignalet viser Kør Igennem").
In case that a train, scheduled to pass the station without stopping, needed to be handed a message, the Signaler could prevent the Entry Signal from showing "Extended Proceed". This form of exchanging messages was abandoned in 1975 but the feature likely remained in the interlocker until the introduction of CTC (ca. 1995).
Originally the combined Entry and Exit Routes through the Siding were not possible. At some point in time this restriction was removed (probably with the introduction of CTC) and at the present it is possible to signal a train through the Siding without stopping. The Entry Signal, however, will only show "Proceed at reduced speed" (Danish: "Kør med begrænset hastighed"). Before this restriction was removed the train would have to enter the Siding and stop before an Exit Route could be set.

"Halt" and "Unmanned Station" functions

Originally, when the station was locally manned and there was no line block towards the neighboring stations, the station could be switched into "Halt" (Danish: Holdested) or "Unmanned Station" modes (Danish: Ubetjent Station). These modes were used at times when traffic did not need the station for meets, and allowed for savings in manpower.

In the "Halt" mode the station was manned by a lower class employee (for example a porter). Meets and other complex operations could not be performed, and as a "Halt" it was only possible to set routes in and out of the Main Track. But the porter could operate the barriers on a manual road crossing and assist in local shunting (which was then performed under the conductor's responsibility).

If the station had no road crossings (or the road crossings were automatic) and no local shunting was to be performed during those hours, the "Unmanned" function could be used instead, thus saving personnel altogether.

In the "Halt" mode it was only possible to set routes in and out of the Main Track. The turnouts could be operated normally and the routes otherwiswe worked as normal. Thus it was possible to shunt at the station but not perform meets or passes. The "Halt" function probably wasn't used much if the "Unmanned" function was available. The "Halt" function was removed when the station became remote controlled in 1995 but had likely not been used in many years.
When the interlocker was switched into "Unmanned" mode Through Routes could be set in both directions simultaneously. The signals would stay cleared and the route would not release as the trains passed. For the departure procedure, however, it was necessary for the train crews to know if a station was unmanned. A signal on the platform would display "Station unmanned" (Danish: "Stationen ubetjent") as triangular white lights in both directions, meaning that the train could depart without the signaler's permission. When the station was manned, this signal was extinguished.
With the new rulebook in 1975 the signaler's departure signal was no longer required on stations with Exit Signals. The "Station Unmanned" signal was obsolete and removed, but the "Unmanned" function itself was retained until the station became remote controlled in 1995.

Local Shunting

If local shunting is to be performed, the turnouts can be switched into a "Local Shunting" mode (Danish: "Stedbetjening"). Local shunting is coordinated between the signaler and the shunting crew.

The operation of the station's centrally controlled turnouts could take place from either a panel on the staition building or from a local switch located near the turnout. At Tistrup station, however, only the panel was implemented. For the keylocked turnouts "Local Shunting" releases the key from the control panel. The Limit of Shunting Signs indicate how far out towards the open line the shunt movement can go without special permission.

Signal functions until 1961

The pre-1961 Distant and Entry Signal aspects and indications represent the original signaling. Apart from the signal aspects and indications, the remaining signal functions were the same unless noted.

In the 1953-1961 signal system an Entry Signal with a Speed Indicator (Danish: Hastighedsviser) would show the permitted entry speed to the station. The Distant Signal, however, would not reflect the entry speed, and trains still had a prescribed track (and thus entry speed) in the timetable. If a train needed to use a different track than prescribed it would have to be informed beforehand, at latest by being stopped at the Entry Signal. The Speed Indicator was merely a way for the train driver to verify that the correct entry route was set.

Entry Route (Danish: Indkørselstogvej) to the Main Track.
Entry Route to the siding. Please note that the post-1961 Distant Signal shows "Caution" (Danish: "Kør Forsigtigt") in this situation, which was the main purpose of the modification.
Degraded signaling, failure preventing "Proceed".
Exit from Main Track.
Exit from Siding.
Through Main Track.
Through Main Track, message to be delivered.
Halt.
Station unmanned.
Local shunting.