Limit Of Authority

LOA. Movement authorization limit. It is the limit point beyond which the train can proceed at reduced speed if it is safely controlled by the Automatic Train Control (ATC) system. This point is transmitted by the system to each train, so that it is always present, and depends essentially on the safe spacingconditions. In normal situations the updating of the LOA extends the space of movement allowed to the trains; in case of reduction of the LOA, the train must accept this value after the verification by the train itself, to respect safely the most restrictive limit requested; in the absence of this information, ie in a situation of degradation, the train’s behavior must remain safe, generally stopping its march, except for further authorizations. See Movement Authority