Class 01 may refer to: * British Rail Class 01, a class of post-war British 0-4-0 diesel locomotive designed for use on tight curves and limited clearances * DRG Class 01, a class of German standard steam locomotive designed between the wars for express train services * DRG Class 01.10, a later, more powerful version of the DRG Class 01 above first delivered in 1939 * Class 01, in the electrical Appliance classes