Tutorial:Train signals - Revision history

Bilka: typo

2023-02-03T15:56:53Z

typo

← Older revision		Revision as of 15:56, 3 February 2023
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	{{Languages}}		{{Languages}}
	[[Rail signal]]s are necessary to run a functioning rail system in Factorio. This ~~tutorail~~ explains why and how signals are used, how chain signals work, what deadlocks are and how they can be avoided. The aim is to enable the reader to keep a rail system running smoothly and fix common issues. Examples of frequent issues and use cases are shown.		[[Rail signal]]s are necessary to run a functioning rail system in Factorio. This tutorial explains why and how signals are used, how chain signals work, what deadlocks are and how they can be avoided. The aim is to enable the reader to keep a rail system running smoothly and fix common issues. Examples of frequent issues and use cases are shown.

	This tutorial mostly uses rail systems with two parallel rails, one for each direction. For beginners, using this architecture is suggested instead of a single bidirectional rail line, which can lead to issues when more trains are added to the system.		This tutorial mostly uses rail systems with two parallel rails, one for each direction. For beginners, using this architecture is suggested instead of a single bidirectional rail line, which can lead to issues when more trains are added to the system.

Unique 2: Clarify some explanations, change wording in some places

2022-12-02T17:12:59Z

Clarify some explanations, change wording in some places

Show changes

AmericanPatriot: Mentioned that block colors are separate from signal colors.

2021-12-11T05:13:16Z

Mentioned that block colors are separate from signal colors.

← Older revision		Revision as of 05:13, 11 December 2021
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	Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular [[Rail signal\|rail signal]] protects the rail block after it, up to the next signal or the end of the track. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.		Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular [[Rail signal\|rail signal]] protects the rail block after it, up to the next signal or the end of the track. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.

	Rail blocks are shown with colors when a player has a signal in hand. The picture shows the block visualization, there are a total of eleven blocks. Rail signals (and chain signals) break up blocks, train stops do not.		Rail blocks are shown with colors when a player has a signal in hand. These colors are only for visualization: the color of the signal will be displayed on the lights of the signal entity. The picture shows the block visualization, there are a total of eleven blocks. Rail signals (and chain signals) break up blocks, train stops do not.

	[[File:Rail_blocks_example.png\|1000px]]		[[File:Rail_blocks_example.png\|1000px]]

Jasper-bear at 17:10, 13 May 2020

2020-05-13T17:10:52Z

← Older revision		Revision as of 17:10, 13 May 2020
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	{{Languages}}		{{Languages}}
	Rail ~~signals~~ are necessary to run a functioning rail system in Factorio. This tutorial explains why and when signals are used, what deadlocks are and where they can happen. The aim is to enable the reader to keep a rail system running smoothly and fix common issues. Examples of frequent use cases are shown.		[[Rail signal]]s are necessary to run a functioning rail system in Factorio. This tutorial explains why and when signals are used, what deadlocks are and where they can happen. The aim is to enable the reader to keep a rail system running smoothly and fix common issues. Examples of frequent use cases are shown.

	For beginners who are just learning the usage of signals it is recommended to place radars near all intersections to help identify issues quickly. It is also recommended to set up automation for fueling trains as soon as possible whenever a new train or station is added to the system. Trains can either be fueled at one stop on their usual schedule (this may or may not involve transporting fuel to a station) or by adding a separate fuel station to the schedule.		For beginners who are just learning the usage of signals it is recommended to place radars near all intersections to help identify issues quickly. It is also recommended to set up automation for fueling trains as soon as possible whenever a new train or station is added to the system. Trains can either be fueled at one stop on their usual schedule (this may or may not involve transporting fuel to a station) or by adding a separate fuel station to the schedule.

Jasper-bear: /* Signal spacing */

2020-05-11T22:00:27Z

Signal spacing

← Older revision		Revision as of 22:00, 11 May 2020
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	[[File:Deadlock_signal_space.png\|1000px]]		[[File:Deadlock_signal_space.png\|1000px]]

	The image shows a deadlock between two T-junctions. It happened because while a train was waiting at the intersection, its tail end was still in the last intersection. The junctions when taken individually are signaled correctly, however they are too close to each other. One might argue that they form a single big intersection. There are ~~two~~ ways to fix this: the regular signals between the two junctions could be turned into chain signals or the junctions could be moved further away from each other.		The image shows a deadlock between two T-junctions. It happened because while a train was waiting at the intersection, its tail end was still in the last intersection. The junctions when taken individually are signaled correctly, however, given the length of trains using them, they are too close to each other. One might argue that they form a single big intersection. There are three ways to fix this: the regular signals between the two junctions could be turned into chain signals, or the junctions could be moved further away from each other, or all trains could be shortened.

	After an exit signal of a junction, the next signal must be at least far enough away to fit the ''longest'' train in the rail system between the signals. In general, after every regular signal there should be at least that much space.		After an exit signal of a junction, the next signal must be at least far enough away to fit the ''longest'' train in the rail system between the signals. In general, after every regular signal there should be at least that much space.

			It is recommended that you choose a maximum train length before designing your rail system, and stick to it. Then rail signal blocks can be spaced according to the maximum length.

	== Splitting rail blocks ==		== Splitting rail blocks ==

TwoPizzas: /* Regular signals and blocks */

2020-03-30T15:38:55Z

Regular signals and blocks

← Older revision		Revision as of 15:38, 30 March 2020
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	[[File:Why_signals.gif]]		[[File:Why_signals.gif]]

	Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular [[Rail signal\|rail signal]] protects the rail block ~~behind~~ it, up to the next signal or the end of the track. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.		Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular [[Rail signal\|rail signal]] protects the rail block after it, up to the next signal or the end of the track. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.

	Rail blocks are shown with colors when a player has a signal in hand. The picture shows the block visualization, there are a total of eleven blocks. Rail signals (and chain signals) break up blocks, train stops do not.		Rail blocks are shown with colors when a player has a signal in hand. The picture shows the block visualization, there are a total of eleven blocks. Rail signals (and chain signals) break up blocks, train stops do not.

Unique 2: /* Regular signals and blocks */ Formatting

2018-11-12T21:12:12Z

Regular signals and blocks: Formatting

← Older revision		Revision as of 21:12, 12 November 2018
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	== Regular signals and blocks ==		== Regular signals and blocks ==

	[[File:Why_signals.gif~~\|1000px~~]]		[[File:Why_signals.gif]]

	Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular [[Rail signal\|rail signal]] protects the rail block behind it, up to the next signal or the end of the track. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.		Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular [[Rail signal\|rail signal]] protects the rail block behind it, up to the next signal or the end of the track. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.

Unique 2: Add crashing trains.

2018-11-12T21:00:23Z

Add crashing trains.

← Older revision		Revision as of 21:00, 12 November 2018
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	For beginners who are just learning the usage of signals it is recommended to place radars near all intersections to help identify issues quickly. It is also recommended to set up automation for fueling trains as soon as possible whenever a new train or station is added to the system. Trains can either be fueled at one stop on their usual schedule (this may or may not involve transporting fuel to a station) or by adding a separate fuel station to the schedule.		For beginners who are just learning the usage of signals it is recommended to place radars near all intersections to help identify issues quickly. It is also recommended to set up automation for fueling trains as soon as possible whenever a new train or station is added to the system. Trains can either be fueled at one stop on their usual schedule (this may or may not involve transporting fuel to a station) or by adding a separate fuel station to the schedule.

	== Regular signals ==		== Regular signals and blocks ==

	Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular signal protects the rail block behind it, up to the next signal or the end of the track~~. Rail blocks are shown with colors when a player has a signal in hand, as in the picture (there are a total of 11 blocks in the picture)~~. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.		[[File:Why_signals.gif\|1000px]]

			Whenever there is more than one train on a track, there is the possibility that trains can crash into one another. To prevent trains from doing this, we place signals at intervals along the track and at crossings. A regular [[Rail signal\|rail signal]] protects the rail block behind it, up to the next signal or the end of the track. Signals ensure that only one train can be in any block. Whenever a second train would enter a block that already has a train in it, the train will wait at the signal leading into the block instead.

			Rail blocks are shown with colors when a player has a signal in hand. The picture shows the block visualization, there are a total of eleven blocks. Rail signals (and chain signals) break up blocks, train stops do not.

	[[File:Rail_blocks_example.png\|1000px]]		[[File:Rail_blocks_example.png\|1000px]]
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	== Chain signals ==		== Chain signals ==

	Using signals prevents trains from crashing into each other but brings with itself other potential issues. Every train will wait until the block in front of it is cleared, so trains are waiting for other trains. This becomes a problem when a train starts waiting on an intersection. In that case other trains will have to wait even if they are not going in the same direction. These trains may in turn cause other trains to wait, resulting in a slowdown of the entire system. Traffic systems should avoid having trains waiting on intersections. In Factorio, chain ~~signals~~ are used to ensure that this cannot happen.		Using signals prevents trains from crashing into each other but brings with itself other potential issues. Every train will wait until the block in front of it is cleared, so trains are waiting for other trains. This becomes a problem when a train starts waiting on an intersection. In that case other trains will have to wait even if they are not going in the same direction. These trains may in turn cause other trains to wait, resulting in a slowdown of the entire system. Traffic systems should avoid having trains waiting on intersections. In Factorio, [[Rail chain signal]]s are used to ensure that this cannot happen.

	[[File:Chain-signal-guards-crossroad.png\|1000px]]		[[File:Chain-signal-guards-crossroad.png\|1000px]]

Unique 2: /* Deadlocks */ Fix a deadlock.

2018-11-12T20:03:31Z

Deadlocks: Fix a deadlock.

← Older revision		Revision as of 20:03, 12 November 2018
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	# a rail network that does not allow enough space for trains.		# a rail network that does not allow enough space for trains.

	~~[[File:Signal_deadlock.png\|1000px]]~~

	The image above shows a deadlock caused by missing chain signals since only regular rail signals were used. As a result trains can wait on a crossing which leads to a deadlock. ~~Note that a deadlock~~ can ~~happen with as few as two trains~~. The ~~positions where~~ the ~~regular signals~~ should be replaced by chain signals are ~~marked with hazard concrete~~.		[[File:Deadlock_anim.gif]]

			The image above shows a deadlock caused by missing chain signals since only regular rail signals were used. As a result trains can wait on a crossing which leads to a deadlock. A corrected version of this intersection can be found above. The eight signals before and on the intersection should be replaced by chain signals, the ones leading out of the intersection can stay as they are. As stated above, in general chain signals should be used before and on intersections.

	[[File:Deadlock_too_many_trains.png\|1000px]]		[[File:Deadlock_too_many_trains.png\|1000px]]

	The deadlock in the image happened because there is a circle in the network which was used by more trains than can fit into the circle. To fix ~~the source of~~ the deadlock the circle must be removed.		The deadlock in the image happened because there is a circle in the network which was used by more trains than can fit into the circle. The signals are correct; to fix the deadlock the circle must be removed or less trains need to be routed through this area.

			[[File:Signal_deadlock.png\|1000px]]

			This deadlock also happened because there were too many trains in a too small circle. It shows that a deadlock can happen with as few as two trains. In this case the deadlock could also have been avoided by replacing the marked signal with a chain signal, because it would ensure that only one train can enter the offending circle. However this could lead to trains waiting on the main line, so a waiting area for trains near the station should be added.

	== Signal spacing ==		== Signal spacing ==

Bilka: /* Chain signals */ typo

2018-10-24T15:49:56Z

Chain signals: typo

← Older revision		Revision as of 15:49, 24 October 2018
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	[[File:Chain-signal-guards-crossroad.png\|1000px]]		[[File:Chain-signal-guards-crossroad.png\|1000px]]

	The most important rule is that a train cannot wait for an extended period of time in a block ''after'' a chain signal, whereas it can wait in a block after a regular signal. Since trains should not wait on crossings, this leads to the commonly stated rule: Use chain signals on and before crossings and use regular signals at the exits of crossings. In general, whenever a waiting train would block another train that is going on a different track, a chain signal should be used to prevent the train from waiting.		The most important rule is that a train cannot wait for an extended period of time in a block ''after'' a chain signal, whereas it can wait in a block after a regular signal. Since trains should not wait on crossings, this leads to the commonly stated rule: Use chain signals in and before crossings and use regular signals at the exits of crossings. In general, whenever a waiting train would block another train that is going on a different track, a chain signal should be used to prevent the train from waiting.

	[[File:Double-crossing.gif\|1000px]]		[[File:Double-crossing.gif\|1000px]]