Fuel rail assembly

Various embodiments include a fuel rail assembly for an internal combustion engine comprising: an elongate, common fuel rail having a reservoir for a fuel supply; a plurality of adapters spaced along and fixed to a wall of the fuel rail for hydraulically connecting a respective fuel injector to the reservoir in the common rail; and a respective fuel passage associated with each adapter of the plurality of adapters, each fuel passage directing fuel from the reservoir to the associated adapter. Each fuel passage comprises an inlet end open to the reservoir and an upstream end section adjacent to the inlet end having a length and a cross-sectional area forming a smoothing function to smooth pressure fluctuations in the fuel entering the respective passage.