IRT Dyre Avenue Line part of New York City Subway
Find the relation between <e1>IRT Dyre Avenue Line<\e1> and <e2>New York City Subway<\e2>.
In the New York metropolitan area, the Metropolitan Transportation Authority (MTA) runs the New York City Subway, which is mostly manually operated. The subway system currently uses Automatic Block Signaling with fixed wayside signals and automatic train stops. Many portions of the signaling system were installed between the 1930s and 1960s. Because of the age of the subway system, some replacement parts must be custom built for the MTA, as they are otherwise unavailable from signaling suppliers. Additionally, some subway services have reached their train capacity limits and can not operate extra trains with the current system. There are two different schemes of signaling in the system. The most used scheme is found on all of the B Division, which consists of lines originally built to the Brooklyn – Manhattan Transit Corporation (BMT) and Independent Subway System (IND)'s wider specifications, as well as on most of the A Division, which consists of lines built to the narrower specifications of the Interborough Rapid Transit Company (IRT). An older system was used on all of the A Division, but with the conversion of the IRT Dyre Avenue Line signals to the B Division scheme, this system is no longer in use. As part of the modernization of the New York City Subway, the MTA has plans to upgrade much of the system with communications - based train control (CBTC) technology, which will control the speed and starting and stopping of subway trains. The CBTC system is mostly automated and uses a moving block system – which reduces headways between trains, increases train frequencies and capacities, and relays the trains' positions to a control room – rather than a fixed block system. This will require new rolling stock to be built for the subway system, as only newer trains can use CBTC. 
IRT Dyre Avenue Line New York City Subway