Steilacoom explores the rhythms and spectra of freight trains through synthesis and spatial transforms. The piece attempts to deconstruct field recordings of freight trains in time, space and spectrum and to reconstruct them by processing these field recordings and also by using percussion and noise as a sort of resynthesis. The result is a combined soundfield of real trains, synthesized trains and percussion. The piece is also an exploration of the doppler effect and uses a custom 3D doppler shifter (which includes distance, high freqeuncy damping and reverb cues) in SuperCollider made with the Ambisonic Toolkit to make sounds realistically move around in space and also come from far away and pass through the sound field. Freight trains were recorded using the SoundField 3D microphone on the Puget Sound in Steilacoom, Washington, where the piece gets its title.