Hi 😉 if @derek_gardner tried to explain in 'Google' Italian ,,,
Samuel #14 = Send 40 ANY Trainsets
... you can send Set whatever you want, just make sure that the you pay attention to the Setrules
Pay attention to the SET symbol in the yard and trains manager, this will show you if a SET is complete.
more Info → http://trainstation.wikia.com/wiki/Category:Train_Sets