|First Appearance||Beta 1.5|
|Type of Block||Non-solid Block|
|Data Values||Hex: 1C|
Detector Rails are a type of rail that acts like a pressure plate, and the first rail switch.
When any kind of Minecart is on top of the Detector Rail, it will generate a redstone signal. The signal will be transmitted to blocks that are adjacent to the detector (including Powered Rail) and redstone placed under the rail, like pressure plates.
Detector rails can be used for many things. One train station-like feature could be activating a Note Block to indicate that a minecart is approaching, or a note block in conjunction with a redstone torch to have a grade crossing signal. It is easiest to simply wire a series of 4-6 detector rails, one around every 20 blocks, to a note block and an inverter that powers a Redstone Torch. As the cart passes each detector rail, it will trigger the circuit for one flash of the torch and a chime, thus giving you 4-6 chimes before the cart reaches the crossing. Additionally, they can be used to create a one-way gate to a Powered Rail, with any carts coming the other way slowing down if not stopping completely. They also can be used to activate dispensers to create a minecart-friendly mob trap.
- When the detector rail was first added to the game it could not be placed next to any rail without the game crashing due to a bug.
- If a detector rail was placed on a slope and the next rail had the opposite slope, the detector would only generate signals for occupied carts (like a stone pressure plate). This bug was fixed in update 1.6.
- If a detector rail is on a slope with a powered rail adjacent to it on flat ground, the Detector will not activate it when a Minecart runs over it.