動(dong)(dong)車、全稱動(dong)(dong)力(li)(li)車輛，是指軌道(dao)交通系統(tong)中裝有(you)動(dong)(dong)力(li)(li)裝置的車輛，包(bao)括機車和(he)動(dong)(dong)力(li)(li)車廂兩(liang)大類。動(dong)(dong)車裝配有(you)驅動(dong)(dong)車輪，而與之相(xiang)對應地無驅動(dong)(dong)裝置車輛就是拖車。列車要能在軌道(dao)上正(zheng)常運行(xing)，就必須有(you)動(dong)(dong)車為整列火車提(ti)供足夠牽(qian)引力(li)(li)，但可以不掛沒有(you)動(dong)(dong)力(li)(li)的拖車。