Buildcraft

Buildcraft is a techmod which dates back to beta being one of the first tech mods and dates back since into the current 1.7.10 version. Nowadays Buildcraft is known for its pipes which are used to transport fluids, items and energy in the form of Redstone Flux which is used to power machines.

Overview
The major feature of BuildCraft is the pipes. Pipes are used to transport items, fluids, and mechanical energy between inventories/machines. There are many different types of pipes all with unique functions, including Wooden, Cobblestone, Stone, Sandstone, Iron, Gold, Diamond, Emerald and Obsidian. Pipes can be combined with Pipe Sealant to allow them to make Fluid Pipes that can transport liquids or with Redstone to make Kinesis Pipes to allow them to transport mechanical energy.

Wooden pipe
The wooden pipe is used for extracting items from chests, furnaces and mod items. They require power directly from an engine to work, and cannot be powered with conductive pipes. They also are the most basic pipe, both in capabilities and rarity of items that are needed.

Wooden pipes will not connect with each other. They can connect to any other transport pipe available, a machine with a valid output slot, or a box. When placed, the brown shaded end of the pipe extracts items from whatever it is connected to and the unshaded end will input the items into a connected container or pipe. The orientation of the pipe can be cycled through valid positions using a wrench. Wooden pipes can be sealed to make them fluid pipes or crafted with redstone to make kinesis pipes to transfer energy.

Cobblestone-Stone-Quartz pipe
Used for transporting items/energy/fluids they wont connect to a pipe of one of the others materials, the only difference they have between each one is that Stone has more drag than Cobblestone, meaning they go slower if they are first accelerated with a Gold pipe and Quartz has more drag than Stone.

Gold pipe
The gold transport pipe will accelerate items/fluids/rf that pass through it. A single segment of gold pipe will give items a small boost of speed. Multiple connected segments of gold pipe grant significantly greater acceleration.

Sandstone pipe
Sandstone pipes connect to other kinds of pipes, allowing stone and cobblestone pipes to connect, but will not connect to any other blocks allowing more piping around machines.

Gates
Gates allow you to change the way your pipes work, including detecting whether items are going through them and many other useful tasks.

Engines
Engines are used to power machines in Buildcraft, they run in Redstone Flux so you can also use them to power other machines compatible with the power type, but they arent very convenient as they produce very little rf per tick (one second is equivalent of 20 ticks) so other options that are provided by other mods might do the same work on a more efficient way. The energy output from an engine only occurs on the top side. Engines can be rotated if they are not facing the right way using a wrench. When right clicked with a wrench, an engine will automatically face towards something it can power. If there is nothing to power, it will not change. Engines must be switched on by a lever or redstone current to function.

Redstone Engine
edstone engines are the most basic engine. When applied with redstone current, it will be powered forever until you turn it off. They supply the least amount of rf/t that wont be able to power any machine in Buildcraft except for the pump. Use this with pipes instead.

Stirling Engine

This mid-range engine is significantly more powerful than the Redstone Engine but uses burnable fuel, such as wood or coal.

Combustion Engine

The highest tier of engine. You can attach a conductive pipe or kinesis pipe (same thing, different versions and APIs) to transport the energy elsewhere. Combustion engines are expensive, and can overheat and explode unless you pump water into it to cool it off. A Combustion Engine can be fueled by pumping oil or fuel into it

Creative Engine

MAWPC version of engine, hit it with a wrench to change the power output.