Difference between revisions of "Minecart"

{{Quality|Masterwork|08:15, 19 May 2015 (UTC)}}

Just like wheelbarrows, minecarts are considered [[item]]s and are stored in a [[furniture]] [[stockpile]]. Despite their five-times-greater capacity, they are only 33% larger than wheelbarrows and are identical in base [[item value|value]] when made from the same [[material]] (the value may differ due to the [[item quality]]). [[thief|Thieves]] or even mischievous animals can steal minecarts, even when they are moving on a track{{cite forum|109460/3289070}}. However, minecarts moving fast enough or being ridden cannot be stolen.

Although most of the utility of minecarts is in [[fortress mode]], an [[adventure mode|adventurer]] can also ride in a minecart. Adventurers can also pick up and relocate minecarts.

Minecarts can be used to swiftly transport dwarves, [[flow|fluids]], and/or large amounts of items, but before you have a functional minecart there are several preconditions that need to be met. First of all you need an actual minecart, constructed either in a [[carpenter's workshop]] or [[metalsmith's forge]]. For the minecart to be able to move you also need to carve (with {{k|d}} {{k|T}}) or construct (with {{k|b}} {{k|C}} {{k|T}}) a track, which could be as simple as a straight line. Finally you need to construct stops on your track (with {{k|b}} {{k|C}} {{k|S}}) where the minecart will start and stop.

After you have created the stops and assigned a cart to the track, you must create logic routes connecting several stops and designate starting conditions for each stop. This is done with the {{k|h}}auling key. The most basic conditions are how the cart's movement is initiated and in which direction the cart should start moving. Carts can be either be Pushed (a dwarf stands at a stop and gives the cart a single push) or Guided (a dwarf continually pushes the cart forward, guiding it along the track). The [[hauling]] [[labor]] required for pushing and guiding carts is called "Push/Haul Vehicles" and is turned on by default.

To control which items to transport you can add conditions specifying: (1) which kind of items to be loaded, and unloaded, (2) stockpile links to define which stockpile(s) the items should be un/loaded to and from.

Minecarts have five times the [[Weight|capacity]] of [[wheelbarrow]]s.  

The weight of the loaded minecart does not affect the initial velocity received from pushing or launching from a roller. However, the load of a minecart ''does'' affect whether a [[pressure plate]] triggers or not, based on the pressure plate's setting.

| [[Bismuth]] (moods only) || 391 || 9 || 15

| [[Electrum]] || 596 || 4 || 7

Minecart tracks are made up of contiguous track, tracked ramp, or bridge tiles. Track tiles and tracked ramp tiles have a direction or series of directions associated with them. These directions dictate which directions a minecart on a given tile may move from that tile. For example, a Track NE (northeast) tile allows a minecart on it to move either north or east from its present position. Therefore, if you want your minecart to move east along a straight piece of track, then return west using that same track, you would need to use EW tracks so that the cart could travel east initially, then return west over the same track. Excluding designs in which the cart will "jump" tracks via a drop or other ramp, tracks must be valid end to end to work for most looped or straight-track applications. A single east only track tile in your line of east-west tracks will cause any route using the track to fail the moment it tries to go the wrong way over that tile. Minecart tracks can be built in two ways: Engraved/carved or constructed. A given minecart track need not use engraved or constructed elements exclusively, as the two methods can be used interchangeably depending on the needs of a given section of track. The way the tracks are built is slightly different between the two, as explained below.

A single-tile wide strip of natural stone can be designated to be [[Engraver|carved]] (with {{K|d}} {{k|T}}), which will create a straight two-way track. The creation of corners, crossings, and T-junctions is as simple as designating another strip of track that overlaps an existent or newly designated track. Engraved tracks are removed by [[smoothing]] the rock they're on, which results in a smooth floor (that can be re-engraved if necessary), or by building a [[floor]] on top and subsequently removing it.  Dwarves can carve corner tracks in one pass by designating the track carving twice and canceling unwanted carvings (with {{K|d}} {{K|x}}). Tracks can be engraved in any natural floor tile, rough, smooth and even over engravings, providing an easy method to remove low-quality or undesired floor engravings. Once a track has been engraved, it's important to check the track directions for each tile in the route carefully to make sure no mistakes were made by yourself or the game's track engraving logic.  

Tracks can also be built as regular [[construction]]s (through {{K|b}} {{K|C}} {{K|T}}). This method is resource-expensive, since each track tile requires one stone, [[bar]], or [[block]] for construction, and time-consuming, since you can't designate strips longer than 10 tiles at a time. Corners, crossings, T-junctions, and ramps also have to be designated individually. However, it is usually the only way to build tracks above ground or on soil (barring the [[Obsidian farming|creation of obsidian]]). Constructed tracks are designated for removal like any regular construction; be aware that removing track ramps built on top of natural ones will also remove the original ramp, leaving a flat floor.

The carving of natural ramps is a little more confusing: to carve a two-way track on a ramp (natural only, does not work on constructed ramps), you must designate the track '''starting on the ramp and one square beyond''' in the direction you want the track to go. For the side of the ramp square you want to head upward, there '''must''' be either a natural or constructed wall in the square next to it, otherwise the game assumes you are trying to carve it on the same level -- this can result in the track being carved underneath a door or other object. If you have accidentally done this, you can correct it by smoothing the ramp and constructing a single square of wall next to it, then re-carving the ramp correctly. (However, the wall must stay there permanently; removing it will disconnect the track.)

When constructing track ramps, the stated direction should be the same as the connected tracks. For example, a track going up from West to East would require, starting from the West, a Track (EW), a Track/Ramp (EW) and a Wall behind the ramp, underneath the section of track above it. Incorrectly placed ramps result in minecarts ignoring the ramp and crashing into the supporting wall. They will not, however, display as unusable as when the supporting wall is missing.

  =▲░░   ░░▼░░  

Moving to and from ramps (or between ramps "pointing" in different directions0 causes some non-trivial adjustments to speed and even moving along the tiles at a fixed speed ''unrelated to the entry/exit velocity values'', because transitions to/from ramps are processed differently and are not to be "skipped". This affects compact track/ramp combinations (such as e.g. a simple 2x2 ramp spiral) most, and combined with bouncing often makes them work not in the way one could expect. {{cite forum|144328/5705102}}

 

{{anchor|Tracks}}

Stops are the individual waypoints that make up a hauling route. A given stop consists of the location of a tile, as well as conditions describing when, where, and how a cart should be moved after being stopped at that tile. Stops can be created from within the {{k|h}}auling menu, by placing the cursor over a tile and hitting {{k|s}} while highlighting the route (or a stop within) you've already designated. A minecart will begin its route at the first stop created, and continue through each subsequent stop, being guided, pushed, or ridden from each stop to the next depending on the conditions specified. In many basic minecart applications, the cart will end up at the same stop it began at, though this is not always the case. It is important to note that hauling stop order is enforced, even if there is no track.  A dwarf will drag the cart overland back to a skipped stop in the route's list if your tracks bypass it somehow.

Once a stop has been placed, it is given a default set of conditions under which to move the minecart if it is stopped there. Each new stop gets the same default conditions regardless of the track it is placed upon (e.g. guide the cart to the north). For this reason new stops might get marked by yellow exclamation marks ({{DFtext|!|#ff0}}) due to invalid directions. One important thing to note is that as you place additional stops, the display will show paths between the stops you have defined. However, this is '''not''' necessarily the actual route the minecart will take once the route is in operation. For example, if a route were defined with two stops at opposite ends of a track with many twists and turns, a line will be drawn directly between those stops to show the order in which they will be visited. These route lines may crisscross all over the tracks, but so long as the track is valid end to end, the cart will follow the track from one stop to the next, even across twists, turns, and z-level changes. Stops, which are the steps that make up a route, should not be confused with Track Stops, described below.

A Track Stop, not to be confused with a route stop, is an optional, single-tile construction which serves two purposes. First, it can be used to cancel a cart's momentum in order to slow or stop it as it passes over the Track Stop. This might be necessary if a cart were pushed down a series of ramps to its destination. Second, a Track Stop can cause a cart to automatically dump its contents as it passes over the Track Stop. Track Stops are constructed via {{k|b}} {{k|C}} {{k|S}}, and must be constructed atop an existing piece of track. If a Track Stop has been set to automatically dump a cart's contents, the cart will dump its contents in the direction indicated when it passes over the Track Stop. Depending on the friction settings chosen for the Track Stop, the cart might then stop after dumping, or it might continue on its route to another destination.

Counter-intuitive to their construction method, Track Stops are considered [[building]]s and must be removed by {{k|q}} {{k|x}}.

[[File:minecart-example-1.png|Stockpiles designated.]]

[[File:minecart-example-2.png|Track carving designation.]]

[[File:minecart-example-3.png|Track carved.]]

When the track has been carved, it will look like the above (the track will be solid instead of flashing).  Now, order a track stop to be constructed next to the output stockpile:

| [[File:minecart-example-4.png|Track stop designation.]]

| [[File:minecart-example-5.png|Select dumping direction.]]

You must press {{k|d}} three times to select the dumping direction ''before'' placing the track stop.  We want our blocks to be dumped into the output stockpile east of the track stop.  Then wait for a mechanic to come along and build the track stop.

[[File:minecart-example-6.png|Track stop constructed.]]

Now we'll define the actual ''route''.  This is done in the {{k|h}}auling menu. Press {{k|r}} to begin defining a route. Next, move the cursor to the input end of the track, and then press {{k|s}} to define the first stop:

| [[File:minecart-example-7.png|Stop 1 designation.]]

| [[File:minecart-example-8.png|Route definition, in progress.]]

Move the cursor again, to the output end of the track, and press {{k|s}} again to define the second stop:

| [[File:minecart-example-9.png|Stop 2 designation.]]

| [[File:minecart-example-10.png|Route definition, two stops.]]

| [[File:minecart-example-11.png|Stops are not defined yet.]]

There are several user interface features to note at this point.  The stops have been positioned, but they haven't been ''defined'' yet, so there is a warning {{DFtext|!|#ff0}} symbol by each of them.  In the lower right corner, we see what the {{DFtext|!|#ff0}} means.  Also, note that the second stop is labeled in white, while the other two lines are grey.  The white text is a selection indicator, and can be moved up and down by pressing {{k|+}}/{{k|-}}.

Next we need to define what our stops do.  We want the minecart to be filled with blocks at the first stop, then travel to the second stop where it will dump its cargo, and then return.  Press {{k|-}} to move the selection up to stop 1, and {{k|Enter}} to open it up. By default, the stop has three conditions:

[[File:minecart-example-12.png|Default stop definition.]]

We don't want any of these, so press {{k|x}} three times to delete them.  This leaves us with a blank stop.  Now we can add the conditions we actually want.  Press {{k|n}} to begin adding the first condition, then {{k|d}} twice to change the direction from north to east.  Then press {{k|c}} to change the condition from empty to full.  This will instruct the minecart to be guided east when full of desired items.

To set the desired items, we create a stockpile link. Press {{k|s}}, then move the cursor to the input stockpile, then press {{k|p}} to select that stockpile.  Now press {{k|Enter}}; this opens up a selection screen that resembles the stockpile customization screen.  Move down to Blocks, {{k|e}}nable them, then (if you wish) restrict it to stone blocks.

When you've done all that, stop 1 should look like this:

[[File:minecart-example-13.png|Stop 1, defined.]]

Stop 2 is much simpler. All we need to do is have the minecart return to the input stop. So, make a condition and change the direction:

[[File:minecart-example-14.png|Stop 2, defined.]]

Finally, we just have to assign our minecart.  Go back to the route definition screen, and press {{k|v}}.  Select the minecart, and press {{k|Enter}}.

Now we've got everything set up:

[[File:minecart-example-15.png|Route, fully defined.]]

 

The V is red because the minecart hasn't been moved onto the track yet. Some dwarf will have to haul it from the forge to the first stop, by hand; this will take a while, especially if the forge is far away.

 

Once the minecart is in place, dwarves should fill it with blocks from the input stockpile, which will in turn be filled with blocks from the workshop where your mason has been toiling dutifully. When the minecart is full, the blocks will be dumped into the 1x1 stockpile on the right.  Automatic quantum dumping!

Because of the complexity of the system, all but the most careful and experienced minecart users will encounter issues. Most route issues can be diagnosed and fixed from the {{k|h}}auling menu.   

'''Possible Causes:'''

* The departure direction of the stop might be invalid. Edit the stop using {{k|Enter}} and press{{k|d}} until it is pointing in a valid direction.

* The track stop might not be built on top of a track. The track stop must be deconstructed to remedy this issue.

* Your track might not be built correctly. Make sure all connected tracks between destinations are not one-way tracks.

** This can be especially confusing with ramps. To carve a two-way track on a (natural) ramp, you must designate the ramp <b>and one square beyond</b> in the direction you want the track to go.

** Ramps '''must''' have a solid block on the side opposite to the track, or they will neither work nor be marked as "unusable". The solid block can be natural or constructed.

* The desired/kept items might not be configured correctly.

'''Possible Causes:'''

* The stop may not be set to take from a stockpile. Edit the Stop using {{k|Enter}} and make sure you see a message like "Take from Stockpile #1".

* The take conditions must correspond with the contents of the stockpile.

* The track stop may be set to dump. A track stop set to dump cannot be filled. You must either set the stop to a time-based departure or deconstruct the track stop and rebuild it without dumping. (Alternatively, with [[DFHack]] you can modify "Dump on arrival" to "No" using the {{key|q}} menu without rebuilding the stop.)

* Make sure the minecart itself has not been designated to be dumped (such as when using mass-dump).

'''Possible Causes:'''

* The minecart may contain items which are not included in its current stop's desired items. Check inside the minecart using the {{key|k}} and {{key|z}} keys and ensure that all items in the cart are desired items.

* The minecart may contain desired items in bins. Minecarts seem to have problems realizing that they are in fact full of desired items if some of those items are in bins, even if bins are also among the desired items for that stop. '''This cannot be solved by adding the appropriate bins to the stop's desired items.''' Either disallow bins in stockpiles you intend to load minecarts from, or set the departure conditions to rely only on percentage of total load rather than percentage of desired items using the advanced conditions menu ({{key|C}} key).

'''Possible Causes:'''

* This can be caused by using a Track Stop with autodumping enabled at a loading site. Every time a dwarf places an item into a cart resting on such a track stop, the item will be immediately dumped, causing unlimited, useless cart loading jobs. Autodumping Track Stops should never be used at a loading site.

* See [[#Quirks|Quirks]]

Track stops are constructions that allow further automation of minecart systems via adjustable features such as braking by friction and automatic dumping of contents. They can be built from logs, bars and blocks through {{K|b}} {{K|C}} {{K|S}}; friction amount, dumping toggle and dumping direction must be set '''before''' construction, and these settings can be neither changed nor seen thereafter; however, track stops can be linked to [[pressure plate]]s or [[lever]]s to toggle friction and dumping On or Off (trigger state is inverted: switch On = track stop Off).  

If a [[stockpile]] is placed on the tile that a track stop is set to dump to, it can act as a [[Exploit#Quantum_stockpiles|quantum stockpile]] and any items dumped from a minecart that match the storage settings of the stockpile will remain there and accumulate.  Normally trackstops are built on top of existing track to operate on moving minecarts, but they can also be used without tracks to create [[Exploit#The_Minecart_Stop|automatic quantum stockpiles]] (see also [[#Step-by-step_tutorial|step-by-step tutorial]]).  It is not always desirable to collect ALL of certain items into one quantum stockpile, such as when distributing a material to multiple separate industries. You can link your quantum stockpile to various other stockpiles, ensuring that your dwarves will keep them supplied as necessary. Because quantum stockpiles never fill up like regular stockpiles, it may be a good idea to add a switch to turn them off.   

Carts can be given momentum without rollers or changing z-level through a phenomenon called "impulse ramps". A track ramp which is connected both to a wall and to a floor will ''always'' accelerate a cart towards the connected floor tile, no matter where the cart enters the tile from. This means carts can be accelerated as though dropping z-levels, even if the cart doesn't actually change z-level at all. If a track ramp faces three directions such as ╩, then two of those directions need to be facing walls for the cart to be accelerated towards the remaining direction.

If a cart enters from the left, it will speed up on every track/ramp and exit to the right going very very fast - more than one tile every step. If it enters from the right then it will bounce back impulsed by the ramp if it's going slow enough.

As another oddity, carts coming from ramps will in some cases "teleport" through most of the next tile. This can be used to send carts up levels with minimal loss of speed. You can just make an upward spiral alternating impulse ramps and regular upward ramps. It takes no power, is quick and cheap to build, requiring only channeling and track carving, and the cart goes up fast, but not so fast that it launches its contents.

Example of an impulse elevator:

Note that this impulse elevator, due to the checkpoint effect and upward ramp curve effect, will not actually result in carts traveling straight up the ramp.  They will lose speed, bounce off a ramp, then be accelerated back into the spiral after a 9-turn delay on both tiles on the floor where they are stopped.  This is because the checkpoint effect allows carts to travel up the ramps in a single turn, but also prevents the impulse ramps from adding acceleration unless the cart is slowed to staying on the ramp for more than one turn.  Initial acceleration will carry the cart up a variable number of floors before this effect occurs, but this bouncing back and forth will occur every 5 z-levels after the first time the cart stops.  When the cart ''is'' traveling upwards, it will pass every tile at a rate of one tile per turn regardless of its actual speed, due to the checkpoint effect.  In tracks with only a single cart, this is negligible, but when multiple carts are on the same track (such as when you place multiple carts on a magma cart lift) this can cause collisions which derail carts or cause other unexpected or undesired behaviors.

The following impulse ramp (while larger) should alleviate these problems with additional impulse ramps that actually have enough time (more than one turn) to add speed (although a derail checkpoint may be required to prevent excessive speeds):

  ░░░░░░  ░╔╔═░░  ░▼▼▼╗░   ░░░░▼░

  ░╚▼▼▼░   ░▼░░░░   ░░░░░░  ░░═╝╝░

Also, if you want to have a cart following a regular speed, the following track works well:

As constructions or tile features, [[door]]s and other furniture can be built on tracks. A [[door]] or [[floodgate]] can be turned on or off by a [[lever]], effectively controlling the flow of automated minecarts. This may be <s>dangerous</s> [[fun]], however.  

This behavior can be used to build a "speed limiter", that will ensure that when a minecart exits it is traveling below derail speed:

Dwarves can admire buildings while riding mine carts. Dwarves will not fall asleep during a ride (at least not from being drowsy). If riding on a continuous powered track loop, the dwarf will die of dehydration/starvation as they can not jump off to get sustenance{{cite forum|109460/3377228}}. Dwarves riding in submerged minecarts will gain experience in [[swimming]].{{cite forum|129889}}

When set to "Push" or "Ride", minecarts will move according to the regular laws of momentum, gaining speed when going downhill, losing it slowly due to friction when on a flat plane, and more quickly when going uphill. In these modes, minecarts will move in a straight line until they either are brought to a stop by friction or an obstacle, or until they encounter a turn. A minecart will roll straight past "blocked" ends of T-junctions or track ends, they have no power to restrict a cart's movement. The cart's behavior is largely independent of the weight of its contents (including fluids and dwarves): heavily loaded carts gain more momentum when accelerating, but this only plays a role in collisions: a heavy cart gains just as much speed and is as easy to stop as a light one. In either case, dwarves can not push nor ride an unpowered cart up a ramp, bouncing back the direction it came. At best, this is a waste of time; at worst, it will give your cart-pushing dwarf a [[fun|fun surprise]]. To solve this, the player can either use Rollers (see below) or set the cart to be Guided.

{{DFtext|Push}}: the dwarf will give the cart an initial push, not enough to go up a ramp, but enough to go some way along flat track, and the dwarf will remain at the first stop, ready for a new job.

{{DFtext|Ride}}: the dwarf will give the cart the same initial push and then hop aboard the cart riding with it to the next stop.

{{DFtext|Guide}}: minecarts seem to ignore all laws of physics. That is:

*Ignore the weight of any and all items inside. Therefore:

**Move at the speed of the dwarf that is guiding them. It is thus recommended to pick the most [[attribute#Agility|agile]] of your dwarves for cart-guiding tasks.

*Ignore working rollers.

*Will go up ramps like nobody's business.

This is therefore the recommended method of transport for simple non-powered rail systems, despite it diverting a dwarf from other, potentially more important tasks.

=== Track Direction Irrelevance ===

This means, for example, that the following tracks, when a (non-guided) cart travels from West-to-East, are functionally identical in effect:

This is because so far as the cart is concerned, only ramps and curves with two exits where the exit in the path they are traveling matters.

Carts only check for curves when they are halfway through a tile.  When they get there, they look to see if their path has no exit.  (That is, if it is traveling East, it checks if there is an East exit.) If there is, it ignores all other track directions, and keeps traveling.  If there is not, it checks to see if there are only two exits to the track, and if one of those directions was the direction it "came from".  (That is, if traveling from the East, it checks if there is a valid exit to the West, and if so, if there is either a North exit or a South exit.) If there is not, it ignores the track anyway, and keeps on traveling as though it were still on track.  If there is, it will subtract 1000 from the velocity of the cart, and redirect all forward velocity to the direction of the curve.  This change in the direction of velocity ''overwrites'' any "diagonal" velocity, which can prevent diagonal velocity derailments, but any perpendicular velocity is not preserved, and is instead discarded.

Ramps are functionally defined for cart purposes as being a tile which exerts an acceleration force upon its "downward slope".  This downward slope requires a cart to have one ''and exactly one'' carved exit to the tile that is the "bottom" of the ramp.  Ramps push carts in this "downward" direction (possibly leading to diagonal movement, below), and the deceleration of an "uphill" ramp is actually just the acceleration being applied against the direction of a cart's movement. 

 

 

 

 

 

 

 

 

Corners on upward ramps can cause diagonal movement, forcing a derail even if the cart has a wall next to it, which will force a stop when it touches a wall that forces dwarves to manually reset the cart. 

 

 

 

The checkpoint effect, [http://www.bay12forums.com/smf/index.php?topic=144328.0 explained in depth by Larix], is an odd and highly exploitable feature of ramps where minecarts "teleport" through the next tile of track, ignoring nearly all minecart physics (except that they stop at all walls or other obstacles and not only respect curves, but will take them even when they would otherwise derail) and passing through that tile in just a single tick, and into the next tile at the halfway point. 

 

 

 

This [[bug]] is the cause of a ''wide array'' of unexpected behavior among people who do not take this bug into account.  It causes derailments or failure to climb up seemingly valid impulse elevators.  In general, it makes a system that behaves extremely counter-intuitively, and operates ''any time a cart encounters a valid ramp''.  At the same time, when its effect is accounted for, it is highly exploitable: It causes "perpetual motion devices" using no power when two opposing ramps are placed next to one another, since the "uphill" effect of the opposing ramp is ignored, preventing deceleration.

 

 

The cart falling (from a hatch, thus with no horizontal speed) onto a track ramp is accelerated as if starting from the middle of the ramp - i.e. to the same speed, no matter how many Z-levels it was dropped, vertical velocity is negated. {{cite forum|144328/5701211}}

 

 

 

 

 

 

 

 

 

 

Every tick the cart accumulates distance units, as well as slows down depending on current tile (speed is reduced by "friction" of the tile). The cart will move to the next tile the tick before accumulating 100000 distance units, (or several tiles in case of great speed), then the leftover distance units are added to the default 100000 distance u. of the next tile. Since most deceleration and acceleration is applied per step, with the notable exception of corners, a cart going at twice the speed of another one can cover about four times the distance in a straight line, but only twice the distance along a winding track with very many corners.

 

A push will teleport a cart to the beginning of the next tile (NOT the middle!) in one tick with 19990 speed (10 speed is lost due to track friction), while a roller will give a cart the roller's set speed, and it will start to accumulate regular track friction past the middle of the roller tile. Some track features will affect a minecart when it is past the middle of the previous tile: entering a ramp or a hole/drop will happen when the cart has left the middle of the previous tile, and the ramp will gain additional distance unit depending on the leftover units from the previous tile. When a cart leaves a ramp it will emerge after one tick in the middle of the next regular tile, so its entry coordinate is "50000-speed+friction". Rollers also affect the speed of minecart from the middle of the previous tile.

Water of depth 7/7 provides a friction of about 10000 per step, as does maximum-depth magma. This higher friction may not apply to very slow-moving carts.