A train component is composed of several parts, including a CAR, SLEEPER, railcar, and BOXCAR. A CAR is a three-letter word that refers to a vehicle used for transportation, usually on rails. A SLEEPER is a seven-letter word that refers to a type of railway CAR that has sleeping accommodations. A railcar is also a seven-letter word that refers to a railway vehicle with no locomotive. Lastly, a BOXCAR is a six-letter word that refers to a railway freight CAR with sides and ends of rectangular shape and doors in the end walls.