Minecart with Command Block

The Minecart with Command Block is a Command Block inside a minecart, having the combined functionality of both. It can be activated by powered Activator Rails.

Obtaining
Much like regular command blocks, the minecart with command block is only obtainable using (using "minecraft:command_block_minecart") or external tools. It can also be obtained through, like the other different types of minecarts can.

Usage
The minecart with command block is used to run commands and travel. It can be more useful than a Command Block in some situations, and less useful in others. For an example, a benefit of command block minecarts is that you do not need to give it input from a Clock circuit; for as long as it is powered, it will repeatedly run the command, once every four game ticks (five times per second). Relative coordinates can be very useful in Minecart Command Block commands. For example, giving the XYZ as "~6 ~2 ~0" (without the quote marks) means "the block that is 6 South and 2 up from the minecart's current location". Since the minecart's location is constantly changing, a setblock command using relative coordinates can draw a wall (poorly, with gaps).

Trivia

 * Minecarts with Command Blocks will repeatedly execute their command when on a powered activator rail, unlike the regular Command Block which executes its command only once until it is powered again.
 * When broken, the Minecart with Command Block will only drop a Minecart rather than both a Minecart and Command Block.
 * Minecarts with Command Blocks do work with comparators; they will output a signal when they are hooked up to a detector rail that has a Minecart with Command Block that successfully ran a command the last time it was activated via a powered activator rail. Unfortunately this means that you can't use it and the "clock circuit effect" together (because the cart can either be on a detector rail or an activator rail, not both at the same time).
 * Unlike the regular command block an explosion will destroy the Minecart with Command Block. This may be because the cart itself is vulnerable or a limitation of the fact that the code counts it as an entity.