Rail chain signal - Revision history

Laar: /* Definition */

2025-12-17T09:47:28Z

Definition

← Older revision		Revision as of 09:47, 17 December 2025
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	== Definition ==		== Definition ==
	Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, ~~and turns red if~~ the ~~next~~ signal ~~is red~~. ~~In effect~~, this ~~prevents a~~ train ~~from entering a block if it won~~'t be ~~able to leave~~. ~~When more than one exits exist,~~ the ~~one where~~ the train ~~is pathing to is considered~~.		Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to exit signals of the next block. If the exit signal of the next block does not allow the train to pass, then the chain signal will stop the train. If there are multiple exit signals, then the one along the path of the train must be considered.

			A special case for to this rule is when the train's destination can be reached from the chain signal without crossing any other signals. In that case the chain signal will not consider the exit signals. This is valid both for train stops and for temporary stops.

	== Advanced ==		== Advanced ==

Bilka: Reordering with 1.1

2021-03-19T15:19:55Z

Reordering with 1.1

← Older revision		Revision as of 15:19, 19 March 2021
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	{{LogisticsNav}}		{{LogisticsNav}}
	{{C\|~~Transport~~}}		{{C\|Railway}}

Zippy: This format looks smoother, I hope it's alright.

2020-08-18T00:32:31Z

This format looks smoother, I hope it's alright.

@@ Line 9: / Line 9: @@
 == Definition ==
 Both normal signals and chain signals prevent a train from entering the next block if it is obstructed.  However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red.  In effect, this prevents a train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered.
 == Usage examples ==
@@ Line 48: / Line 61: @@
 [[File:chain-signal-prevents-deadlock.png|1000px]]
 == History ==

Unique 2: Fix outdated links, make reference to the signals tutorial more visible

2020-06-12T16:30:26Z

Fix outdated links, make reference to the signals tutorial more visible

← Older revision		Revision as of 16:30, 12 June 2020
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	{{:Infobox:Rail chain signal}}		{{:Infobox:Rail chain signal}}

	'''Rail chain signals''' are used for automated transportation on a [[Railway\|railway network]]. With rail chain signals, it is possible to use multiple trains on a single track, or multiple rails that intertwine.		'''Rail chain signals''' are used for automated transportation on a [[Railway\|railway network]]. With rail chain signals, it is possible to use multiple trains on a single track, or multiple rails that intertwine. Rail chain signals can be used to ensure that trains only enter a crossing if they can also leave it, which ensures that they do not block other traffic by waiting on the crossing. In addition to the explanation on this page, there is also the [[Tutorial:Train_signals\|rail signal tutorial]].

	== Basic ==		== Basic ==
	* The best prerequisite to understand chain signals is to understand [[~~Rail signal~~\| signal blocks]].		* The best prerequisite to understand chain signals is to understand [[Tutorial:Train_signals#Regular_signals_and_blocks\|signal blocks]].
	* Rail chain signals are placed like ~~block~~ signals at the right side of ~~a [[Railway#Rail Glossary\|segment]]~~.		* Rail chain signals are placed like regular signals at the right side of the railway track. If automated trains are required to drive in both directions on the same track segment, signals need to be added on both sides of the track, opposite each other.
	* They work similar to ~~pre-~~signals ~~in OpenTTD~~.

	== Definition ==		== Definition ==

Bilka: The linked guide is not official.

2020-05-12T07:52:44Z

The linked guide is not official.

← Older revision		Revision as of 07:52, 12 May 2020
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	== Definition ==		== Definition ==
	Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red. In effect, this prevents a train from entering a block if it won't be able to leave.		Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red. In effect, this prevents a train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered.

	== Usage examples ==		== Usage examples ==
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	* [[Railway]]		* [[Railway]]
	* [[Tutorial: Train signals]]		* [[Tutorial: Train signals]]

	~~== External Links ==~~

	* The official Factorio Train Automation Tutorial can be found here: http://www.factorioguide.com/factorio-users-guide-updates/written-guides/


	{{LogisticsNav}}		{{LogisticsNav}}
	{{C\|Transport}}		{{C\|Transport}}

Jasper-bear: Added external link to official documentation

2020-05-12T03:11:12Z

Added external link to official documentation

← Older revision		Revision as of 03:11, 12 May 2020
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	* [[Railway]]		* [[Railway]]
	* [[Tutorial: Train signals]]		* [[Tutorial: Train signals]]

			== External Links ==

			* The official Factorio Train Automation Tutorial can be found here: http://www.factorioguide.com/factorio-users-guide-updates/written-guides/


	{{LogisticsNav}}		{{LogisticsNav}}
	{{C\|Transport}}		{{C\|Transport}}

Jasper-bear: /* Definition */ "the chain signal itself has no idea which path the train wants to take, it just knows that some exits are obstructed and some aren’t." -- from https://docs.google.com/presentation/d/1pDj-ccWjUrwG_9_fDzLUosFZx_luGUet5XZwt7uUyzM/edit#s

2020-05-11T22:37:17Z

Definition: "the chain signal itself has no idea which path the train wants to take, it just knows that some exits are obstructed and some aren’t." -- from https://docs.google.com/presentation/d/1pDj-ccWjUrwG_9_fDzLUosFZx_luGUet5XZwt7uUyzM/edit#s

← Older revision		Revision as of 22:37, 11 May 2020
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	== Definition ==		== Definition ==
	Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red. In effect, this prevents a train from entering a block if it won't be able to leave. ~~When more than one exits exist, the one where the train is pathing to is considered.~~		Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red. In effect, this prevents a train from entering a block if it won't be able to leave.

	== Usage examples ==		== Usage examples ==

Jasper-bear: removed info i added that may not be true

2020-05-11T22:35:47Z

removed info i added that may not be true

← Older revision		Revision as of 22:35, 11 May 2020
Line 10:		Line 10:

	== Definition ==		== Definition ==
	Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red. In effect, this prevents a train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered. ~~However, if the destination train stop is in the block, the train is not required to be able to leave the block.~~		Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red. In effect, this prevents a train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered.

	== Usage examples ==		== Usage examples ==

Jasper-bear: /* Definition */ Updated definition based on official document: https://docs.google.com/presentation/d/1pDj-ccWjUrwG_9_fDzLUosFZx_luGUet5XZwt7uUyzM/edit#slide=id.g12a2bb5fc4_884_177

2020-05-11T22:31:33Z

Definition: Updated definition based on official document: https://docs.google.com/presentation/d/1pDj-ccWjUrwG_9_fDzLUosFZx_luGUet5XZwt7uUyzM/edit#slide=id.g12a2bb5fc4_884_177

← Older revision		Revision as of 22:31, 11 May 2020
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	== Definition ==		== Definition ==
	~~While~~ normal ~~signal prevents~~ train from entering the ~~occupied~~ block, chain signal prevents train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered. However, if the destination train stop is in the block, the train is not required to be able to leave the block.		Both normal signals and chain signals prevent a train from entering the next block if it is obstructed. However, a chain signal also looks ahead to the next signal, and turns red if the next signal is red. In effect, this prevents a train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered. However, if the destination train stop is in the block, the train is not required to be able to leave the block.

	== Usage examples ==		== Usage examples ==

Jasper-bear: /* Definition */

2020-05-11T22:11:36Z

Definition

← Older revision		Revision as of 22:11, 11 May 2020
Line 10:		Line 10:

	== Definition ==		== Definition ==
	While normal signal prevents train from entering the occupied block, chain signal prevents train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered.		While normal signal prevents train from entering the occupied block, chain signal prevents train from entering a block if it won't be able to leave. When more than one exits exist, the one where the train is pathing to is considered. However, if the destination train stop is in the block, the train is not required to be able to leave the block.

	== Usage examples ==		== Usage examples ==