A1 A-A1 A AAR Absolute Block System Acceptance Abbreviations Active Suspension Add Value Machines Adhesive Weight Adhesion factor AEIF Air Bags Air Brake Air Dryer Air Suspension Alternator Analogue E-P Brake Control Angle Cock Articulation Aspect Asynchronous Motor Automatic Brake Automatic Coupler Automatic Fare Collection (AFC) Automatic Signalling [[Automatic_Train_Control_(ATC)]] [[Automatic_Train_Operation_(ATO)]] [[Automatic_Train_Protection_(ATP)]] [[Automatic_Train_System_(ATS)]] [[Auxiliary_Reservoir]] Auxiliary Supply Availability Axle Axlebox Axle Brush Axle Load