In addition to the commissioning of the unused third platform at Grand Canal Dock the city centre re-signalling scheme will increase the nominal capacity of the line between Pearse and Connolly from about 12 trains per hour per direction to about 20 trains per hour per direction.
Under the revised signalling it will be possible for a northbound train to leave Pearse while the plafform at Tara Street is occupied. Similarly it will be possible to leave Tara Street with a train stationary outside Connolly
Whether the new arrangements actually delivers increased capacity will critically depend on the management of platform occupancy at Pearse, Tara Street and Connolly. The present pattern of operation whereby northern and western diesel operated suburban services idle at Connolly and Tara Street "waiting for time" will clearly have to cease
Currently diesels are scheduled to take 7-8 minutes from departing Pearse to departing Connolly while DARTs are typically scheduled to take 5 minutes. In reality the performance differential trains through this section is less than 30 seconds and scheduling services to take more than five minutes merely generates unnecessary congestion and limits potential throughput.
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