Minecraft:Detector Rail

Template:Infobox block The detector rail is a type of Minecraft:rail that produces a Minecraft:redstone signal while a Minecraft:minecart is on it.

Obtaining

Breaking

The suitable tool to break detector rail is Minecraft:pickaxe. Template:Breaking row Detector rail drops itself when it's destroyed.

Usage

To place a detector rail, Template:Control a detector rail item while pointing at a surface facing the space the detector rail should occupy.

A detector rail can be placed on top of any block whose top face has a rim around the edge, such as any Minecraft:full block, Minecraft:hopper, top slab, upside-down stairs, or top trapdoor. A full list of compatible blocks can be found here.

If a detector rail is updated while on an opened top trapdoor, the rail breaks and drops as an item. Placing a minecart on a detector rail on top of a closed and unpowered trapdoor opens the trapdoor and updates the rail, causing the detector rail to break. If the top trapdoor is powered and closed when the minecart is placed, the trapdoor does not open so the rail does not break. The minecart on the detector rail then powers the trapdoor, meaning the external power source can be removed without causing the trapdoor to change state and break the rail.

When placed, a detector rail configures itself to line up with any adjacent Minecraft:rails (including Minecraft:activator rails, Minecraft:powered rails, and other Minecraft:detector rails), as well as adjacent rails one block up. If there are two adjacent rails on non-opposite sides, or three or more adjacent rails, a detector rail lines up in the east-west direction. If there are no adjacent rails, a detector rail lines up in the north-south direction (but if a rail is later placed to the east or west, the detector rail re-orients itself in the east-west direction even if it is already connected to another rail to the north or south). If a rail it would line up with is one block up, a detector rail slants upward toward it (with multiple options to slant upward to, a detector rail "prefers", in order: west, east, south, and north). Other configurations can be created by placing and removing various rails.

Minecraft:Mobs avoid walking across a detector rail (or other rails), but can be pushed onto them.

It cannot be placed suspended in midair, even with commands.<ref>Template:Bug</ref>

Rail

Detector rails (and other rails) act as "roads" for Minecraft:minecarts. A minecart that enters a detector rail's space from either end of the detector rail continues to move, losing only a little velocity (which can then be increased again with Minecraft:powered rails). A minecart that enters a detector rail's space from the side turns east or south (depending on the detector rail's orientation), or in the downward direction for a slanted detector rail.

Redstone component

File:Comparitor signal strength minecart.png

Example for signal strength of a full minecart (right) and a half-full one (left)

A detector rail becomes powered when any part of any minecart's Minecraft:bounding box comes into contact with it. Every 20th game tick after the rail first becomes powered, it checks whether any minecart is still present and depowers if there are none in contact at that time. This means that the duration of the signal is always a multiple of 20 game ticks (10 redstone ticks). While powered, a detector rail:

• sets adjacent Minecraft:redstone dust to Minecraft:power level 15
• activates adjacent Minecraft:redstone repeaters facing away from the detector rail
• activates adjacent Minecraft:redstone comparators facing away from the detector rail to a level corresponding to the fullness of the minecart if it is a minecart with chest or a minecart with hopper
• strongly powers the block supporting the detector rail if that block is Minecraft:conductive
• activates any adjacent mechanism components, including above or below, such as Minecraft:pistons, Minecraft:redstone lamps, Minecraft:powered rails, Minecraft:hoppers, etc.

File:Detector-comparator-diff.png

Comparators give a signal for a minecart with chest or a minecart with hopper

If the minecart on the detector rail is a Minecraft:minecart with chest or Minecraft:minecart with hopper, an adjacent redstone comparator facing away from the detector rail outputs a power level proportional to the container's fullness, possibly power level 0. For any other type of minecart (including a regular minecart with a mob riding it) the comparator's output is zero. If multiple minecarts are on the detector rail, the comparator reads only the minecart that was placed first.

A comparator can read the contents of a minecart with hopper or with chest on a detector rail through a solid opaque block, as it can with other container blocks.

Mob interaction

Like other types of rails, Minecraft:spiders, Minecraft:cave spiders, and Minecraft:wardens are the only land mobs that can walk onto detector rails.

Piston interactivity

Detector rail can be pushed by the Minecraft:piston, and can be pulled by the Minecraft:sticky piston. However, detector rail breaks and drops as an item when it is unsupported because of being moved.

Data values

ID

Template:Edition: Template:ID table

Template:Edition: Template:ID table

Block states

{{#lst:Powered Rail|block states}}

Videos

Template:Yt

History

Gallery

Screenshots

• Image from Notch’s twitter teasing detector rails.
  Image from Notch’s twitter teasing detector rails.

See also

• Template:BlockLink
• Template:BlockLink
• Template:BlockLink