Railway/Train path finding - Revision history

Wiwiweb: Disabling a train stop no longer causes a repath

2025-07-26T19:40:33Z

Disabling a train stop no longer causes a repath

← Older revision		Revision as of 19:40, 26 July 2025
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	* The train wants to depart from a signal (chain or regular) that it stopped at.		* The train wants to depart from a signal (chain or regular) that it stopped at.
	* The train wants to depart from a train stop.		* The train wants to depart from a train stop.
	* The train is pathing to a train stop that gets disabled.

	=== Destination full / No path trains ===		=== Destination full / No path trains ===

Cardinal: Fixed links.

2025-04-21T20:12:42Z

Fixed links.

← Older revision		Revision as of 20:12, 21 April 2025
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	* A signal (chain or regular) is created or destroyed (all trains are revalidated).		* A signal (chain or regular) is created or destroyed (all trains are revalidated).
	* A rail block changes and invalidates a signal (chain or regular) (all trains are revalidated).		* A rail block changes and invalidates a signal (chain or regular) (all trains are revalidated).
	* [https://lua-api.factorio.com/latest/LuaTrain.html#~~LuaTrain.~~recalculate_path LuaTrain::recalculate_path()] is called on the train by a script.		* [https://lua-api.factorio.com/latest/classes/LuaTrain.html#recalculate_path LuaTrain::recalculate_path()] is called on the train by a script.
	* The train's schedule is changed.		* The train's schedule is changed.
	* The train's braking force gets changed and the train is currently driving normally, arriving at a signal (chain or regular) or arriving at a station.		* The train's braking force gets changed and the train is currently driving normally, arriving at a signal (chain or regular) or arriving at a station.
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	=== User / script generated events ===		=== User / script generated events ===
	* A locomotive that is part of the train is rotated.		* A locomotive that is part of the train is rotated.
	* [https://lua-api.factorio.com/latest/LuaTrain.html#~~LuaTrain.~~recalculate_path LuaTrain::recalculate_path(true)] is called on the train by a script.		* [https://lua-api.factorio.com/latest/classes/LuaTrain.html#recalculate_path LuaTrain::recalculate_path(true)] is called on the train by a script.
	* The train is switched to automatic control when it was previously manually controlled.		* The train is switched to automatic control when it was previously manually controlled.
	* The train is set to go to a station using the "Go to stop" button in the train's GUI.		* The train is set to go to a station using the "Go to stop" button in the train's GUI.

CodeGreen at 18:29, 17 May 2024

2024-05-17T18:29:37Z

← Older revision		Revision as of 18:29, 17 May 2024
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	For calculation it uses a simple [[WIKIPEDIA:A_search_algorithm\|A-algorithm]]<sup>[https://www.factorio.com/blog/post/fff-331]</sup>: The pathfinder first builds a list of non-disabled stops that match the name in the schedule, then searches outward from both ends of the train at once, if applicable, in segments. A segment is an uninterrupted plain sequence of rails, with no intersections, stops, or signals (all of which define segment borders). The cost (distance) is calculated using the following weighting rules:		For calculation it uses a simple [[WIKIPEDIA:A_search_algorithm\|A-algorithm]]<sup>[https://www.factorio.com/blog/post/fff-331]</sup>: The pathfinder first builds a list of non-disabled stops that match the name in the schedule, then searches outward from both ends of the train at once, if applicable, in segments. A segment is an uninterrupted plain sequence of rails, with no intersections, stops, or signals (all of which define segment borders). The cost (distance) is calculated using the following weighting rules:
	* Base cost for a block/segment is the length of the segment (linear grid length along the center of the rail).		* Base cost for a block/segment is the length of the segment (linear grid length along the center of the rail).
	* When the rail block is occupied by a train -> Add a penalty of 2 * length of the block divided by ~~block distance~~ from the start, so the far away occupied paths don't matter much.		* When the rail block is occupied by a train -> Add a penalty of 2 * length of the block divided by the number of blocks from the start, so the far away occupied paths don't matter much.
	* When the rail block is guarded by a [[rail signal]] set to red by the [[circuit network]] -> Add a penalty of 1000.		* When the rail block is guarded by a [[rail signal]] set to red by the [[circuit network]] -> Add a penalty of 1000.
	* When the path includes a train stop -> Add a penalty of 2000.		* When the path includes a train stop -> Add a penalty of 2000.

Supply: /* Repath events */ clarified that a new destination train stop can be picked as seen in FFF #378

2023-12-16T13:35:39Z

Repath events: clarified that a new destination train stop can be picked as seen in FFF #378

← Older revision		Revision as of 13:35, 16 December 2023
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	== Repath events ==		== Repath events ==
	There are a number of events that can cause a train to repath listed below. When one of these conditions is met the game considers possible paths from the ~~trains~~ current location to ~~its~~ destination train ~~stop~~ and will chose the path with the lowest score according to the penalties listed above.		There are a number of events that can cause a train to repath listed below. When one of these conditions is met the game considers possible paths from the train's current location to any train stop matching the destination name in the train's schedule and will chose the path with the lowest score according to the penalties listed above.
	=== User / script generated events ===		=== User / script generated events ===
	* A locomotive that is part of the train is rotated.		* A locomotive that is part of the train is rotated.

Ickputzdirwech: category

2023-09-24T18:56:27Z

Flurki: Grammar and punctuation corrected.

2021-08-31T20:13:30Z

Grammar and punctuation corrected.

← Older revision		Revision as of 20:13, 31 August 2021
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	== Path Revalidation ==		== Path Revalidation ==
	A rail path will be revalidated if any event happens that could make this trains path invalid. If the path is found to be invalid then the game will repath the train. Path revalidation just confirms that the current path is still valid and does not confirm that it is still the best.		A rail path will be revalidated if any event happens that could make this trains path invalid. If the path is found to be invalid then the game will repath the train. Path revalidation just confirms that the current path is still valid and does not confirm that it is still the best.
	The ~~follow~~ events cause path revalidation		The following events cause path revalidation:
	* A rail is destroyed (all trains are revalidated).		* A rail is destroyed (all trains are revalidated).
	* A rail is created and invalidates a signal (all trains are revalidated) .		* A rail is created and invalidates a signal (all trains are revalidated) .

Bilka: Changed penalty section to hopefully be more clear for what penalty applies when

2021-06-01T10:17:05Z

Changed penalty section to hopefully be more clear for what penalty applies when

← Older revision		Revision as of 10:17, 1 June 2021
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	* When the rail block is occupied by a train -> Add a penalty of 2 * length of the block divided by block distance from the start, so the far away occupied paths don't matter much.		* When the rail block is occupied by a train -> Add a penalty of 2 * length of the block divided by block distance from the start, so the far away occupied paths don't matter much.
	* When the rail block is guarded by a [[rail signal]] set to red by the [[circuit network]] -> Add a penalty of 1000.		* When the rail block is guarded by a [[rail signal]] set to red by the [[circuit network]] -> Add a penalty of 1000.
	* When the path includes a train stop ~~that is not the destination~~ -> Add a penalty of 2000.		* When the path includes a train stop -> Add a penalty of 2000.
	* When the ~~path includes~~ a train ~~stop with~~ a train ~~stopped in it~~ -> Add a penalty of 500.		* When the rail block contains a train that is stopped at a train stop -> Add a penalty of 500.
	* When the ~~path includes~~ a train stop ~~with a~~ train ~~stopped in it that~~ doesn't have other valid stops in its schedule -> Add a penalty of 1000.		* When the rail block contains a train that is stopped at a train stop and the train doesn't have other valid stops in its schedule -> Add a penalty of 1000.
	* When the ~~path includes~~ a manually controlled stopped train -> Add a penalty of 2000.		* When the rail block contains a manually controlled stopped train with a passenger -> Add a penalty of 2000.
	* When the ~~path includes~~ a manually controlled stopped train without a passenger -> Add a penalty of 7000.		* When the rail block contains a manually controlled stopped train without a passenger -> Add a penalty of 7000.
	* When the ~~path includes a~~ automatic train without a schedule -> Add a penalty of 7000.		* When the rail block contains an automatic train without a schedule -> Add a penalty of 7000.
	* When the ~~path includes~~ a train currently arriving to a train stop -> Add a penalty of 100.		* When the rail block contains a train currently arriving to a train stop -> Add a penalty of 100.
	* When the ~~path includes~~ a train currently arriving to a rail signal -> Add a penalty of 100.		* When the rail block contains a train currently arriving to a rail signal -> Add a penalty of 100.
	* When the ~~path includes~~ a train currently waiting at a rail signal -> Add a penalty of 100 + 0.1 for every tick the train has already waited.		* When the rail block contains a train currently waiting at a rail signal -> Add a penalty of 100 + 0.1 for every tick the train has already waited.
	* When the ~~path includes~~ a train that doesn't have a path -> Add a penalty of 1000.		* When the rail block contains a train that doesn't have a path -> Add a penalty of 1000.

	== Path Revalidation ==		== Path Revalidation ==
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	== History ==		== History ==

			{{History\|0.18.1\|
			* Train stop at train's starting segment exit is no longer counted into penalty. (Not mentioned above)}}

	{{History\|0.17.38\|		{{History\|0.17.38\|
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	== See also ==		== See also ==

	* [https://gist.github.com/Rseding91/c0d4d08d6feaed618ed4a03f6c6a8fe6 Train pathfinding ~~as of version 0~~.~~16 (Code)~~]		* [https://gist.github.com/Rseding91/c0d4d08d6feaed618ed4a03f6c6a8fe6 Train pathfinding code]
			* [https://www.factorio.com/blog/post/fff-331 FFF #331]
	* [https://www.factorio.com/blog/post/fff-68 FFF #68]		* [https://www.factorio.com/blog/post/fff-68 FFF #68]
	* [[Railway]]		* [[Railway]]

Stevetrov: /* Destination full / No path trains */ Removed repath 128 ticks line as it was misleading / inaccurate after conferring with Boskid.

2021-02-25T15:08:24Z

Destination full / No path trains: Removed repath 128 ticks line as it was misleading / inaccurate after conferring with Boskid.

← Older revision		Revision as of 15:08, 25 February 2021
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	* The train limit of a train stop that is part of the train's schedule becomes not full.		* The train limit of a train stop that is part of the train's schedule becomes not full.
	* The train stop that it currently cannot reach gets disabled or destroyed.		* The train stop that it currently cannot reach gets disabled or destroyed.
	* The path is recalculated every 128 ticks.

	=== Others ===		=== Others ===

Bilka: 1.1.7: When the path includes a automatic train without a schedule -> Add a penalty of 7000.

2021-02-03T16:53:04Z

1.1.7: When the path includes a automatic train without a schedule -> Add a penalty of 7000.

← Older revision		Revision as of 16:53, 3 February 2021
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	* When the path includes a manually controlled stopped train -> Add a penalty of 2000.		* When the path includes a manually controlled stopped train -> Add a penalty of 2000.
	* When the path includes a manually controlled stopped train without a passenger -> Add a penalty of 7000.		* When the path includes a manually controlled stopped train without a passenger -> Add a penalty of 7000.
			* When the path includes a automatic train without a schedule -> Add a penalty of 7000.
	* When the path includes a train currently arriving to a train stop -> Add a penalty of 100.		* When the path includes a train currently arriving to a train stop -> Add a penalty of 100.
	* When the path includes a train currently arriving to a rail signal -> Add a penalty of 100.		* When the path includes a train currently arriving to a rail signal -> Add a penalty of 100.

Bilka: 1.1

2020-12-08T17:48:59Z

1.1

← Older revision		Revision as of 18:56, 24 September 2023
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	* [https://www.factorio.com/blog/post/fff-68 FFF #68]		* [https://www.factorio.com/blog/post/fff-68 FFF #68]
	* [[Railway]]		* [[Railway]]

			{{C\|Railway{{!}}#Railway/Train path finding}}

← Older revision		Revision as of 17:48, 8 December 2020
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	* A signal (chain or regular) is created or destroyed (all trains are revalidated).		* A signal (chain or regular) is created or destroyed (all trains are revalidated).
	* A rail block changes and invalidates a signal (chain or regular) (all trains are revalidated).		* A rail block changes and invalidates a signal (chain or regular) (all trains are revalidated).
	* [https://lua-api.factorio.com/latest/LuaTrain.html#LuaTrain.recalculate_path LuaTrain::recalculate_path()] is called on the train by a script ~~and <code>force</code> is false.~~		* [https://lua-api.factorio.com/latest/LuaTrain.html#LuaTrain.recalculate_path LuaTrain::recalculate_path()] is called on the train by a script.
	* The train is set to go to a station using the "Go to stop" button in the train's GUI.
	* The train's schedule is changed.		* The train's schedule is changed.
	* The train's braking force gets changed and the train is currently driving normally, arriving at a signal (chain or regular) or arriving at a station.		* The train's braking force gets changed and the train is currently driving normally, arriving at a signal (chain or regular) or arriving at a station.
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	=== User / script generated events ===		=== User / script generated events ===
	* A locomotive that is part of the train is rotated.		* A locomotive that is part of the train is rotated.
	* [https://lua-api.factorio.com/latest/LuaTrain.html#LuaTrain.recalculate_path LuaTrain::recalculate_path(true)] is called on the train by a script ~~and <code>force</code> is true~~.		* [https://lua-api.factorio.com/latest/LuaTrain.html#LuaTrain.recalculate_path LuaTrain::recalculate_path(true)] is called on the train by a script.
	* The train is switched to automatic control when it was previously manually controlled.		* The train is switched to automatic control when it was previously manually controlled.
			* The train is set to go to a station using the "Go to stop" button in the train's GUI.
			* A waypoint (train stop without wait condition) is removed from the train's schedule.

	=== Repaths that happen as part of normal train operation ===		=== Repaths that happen as part of normal train operation ===
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	* The train stop a train is heading to is renamed or destroyed.		* The train stop a train is heading to is renamed or destroyed.
	* The train is preparing to stop at a signal (chain or regular) that changes so that the train can now continue.		* The train is preparing to stop at a signal (chain or regular) that changes so that the train can now continue.
	* The train is braking for a signal (chain or regular) it cant reserve ~~and the train is not inside a chain signal block~~.		* The train is braking for a signal (chain or regular) it cant reserve.
	* The train enters a new rail block and can't reserve the next needed signal (chain or regular).		* The train enters a new rail block and can't reserve the next needed signal (chain or regular).
	* The train has waited at a chain signal for a multiple of 5 seconds and there are multiple train stops with the same name as the destination.		* The train has waited at a chain signal for a multiple of 5 seconds and there are multiple train stops with the same name as the destination.
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	* The train is pathing to a train stop that gets disabled.		* The train is pathing to a train stop that gets disabled.

	=== No path trains ===		=== Destination full / No path trains ===
	* A rail gets created.		* A rail gets created.
	* A train stop that is part of train's schedule gets renamed or created.		* A train stop that is part of the train's schedule gets enabled, renamed or created.
	* A train stop that is ~~in its~~ schedule ~~gets enabled, renamed or created~~.		* The train limit of a train stop that is part of the train's schedule becomes not full.
	* The train stop that it currently cannot reach gets disabled or destroyed.		* The train stop that it currently cannot reach gets disabled or destroyed.
	* The path is recalculated every 128 ticks.		* The path is recalculated every 128 ticks.