A solo violin in three dynamic modes -- sustain, tremelo and spiccato -- backed by a string section and bolstered by a Sforzando sax patch and English horn. I really like the English horn; it has a sort of blurry vulnerability that you don't get from oboes or clarinets. 

But the secret sauce that ties them all together is a quiet arpeggiated backing in dotted notes by something called a Harmonum, from LostIn70s.com. You may not even hear it, but it makes a big difference.