The airfoil includes an outer wall bounding an interior and defining a pressure side and a suction side, the outer wall extending axially between a leading edge and a trailing edge to define a chord-wise direction, and also extending radially between a root and a tip to define a span-wise direction, at least one cooling conduit formed in the interior of the airfoil, a tip rail projecting from the tip in the span-wise direction, the tip rail including an exterior surface spaced from an interior surface with a tip surface connecting the exterior and interior surfaces, and a three-dimensional plexus of fluidly interconnected cooling passages provided within the tip rail between the exterior and interior surfaces and fluidly coupled to the at least one cooling conduit. In one aspect, the disclosure relates to an airfoil for a turbine engine. While the compressor air is at a high temperature, it is cooler relative to the turbine air, and can be used to cool the turbine.Д¬ontemporary turbine engine airfoils generally include one or more interior cooling circuits for routing the cooling air through the airfoil to cool different portions of the airfoil, and can include dedicated cooling circuits for cooling different portions of the airfoil. and the cooling air from the compressor is around 500В° C. Temperatures in the high pressure turbine are around 1000В° C. Typically, cooling is accomplished by ducting cooler air from the high and/or low pressure compressors to the engine components that require cooling. Gas turbine engines for aircraft are designed to operate at high temperatures to maximize engine efficiency, so cooling of certain engine components, such as the high pressure turbine and the low pressure turbine, can be beneficial. Turbine engines, and particularly gas or combustion turbine engines, are rotary engines that extract energy from a flow of combusted gases passing through the engine onto a multitude of rotating turbine blades.

Pressure distribution airfoil