System antennas) transmit information such as speed and location from the controllers to Trackside Radio Equipment which relays the data to central computers and to the TTC's Transit Control Centre. The central computers send speed and braking instructions back to the train, whereby the central computers are effectively directing each train. With computers operating the train, trains can operate safely on closer headways than with the fixed block system. CBTC allows more frequent service and increased line capacity. With the old fixed block signal system, the TTC can schedule 25.5 trains per hour on Line 1, occasionally operating up to 29 per hour. With CBTC, the TTC can operate 30 to 32 trains per hour with a more consistent frequency. However, this goal depends on how well the TTC can manage dwell time in stations, crew changeovers and turnaround at terminals. The grade-separated section of Line 5 Eglinton, between Mount Dennis station and Science Centre station, will also use CBTC. Unlike on Line 1, the system on Line 5 will be supplied by Bombardier Transportation using its Cityflo 650 technology. Fixed block signalling (Lines 2, and 4) , fixed block signalling is used on Line 2 Bloor–Danforth and Line 4 Sheppard, and was used on Line 1 Yonge–University until September 24, 2022. It uses wayside signals to give instructions to train operators, which may be automatic block signals or interlocking signals. This system, also called the NX/UR system of signalling, is also used on the New York City Subway, the Chicago "L", and the MBTA subway in Boston. Overview With fixed block signalling, the line is subdivided into blocks – a section of track that can be occupied by a train. Each block is protected by a signal at the start of the block that train operators must obey, with the signal aspects indicating whether it is safe for a train to proceed into the next block. These signals are connected to a trip arm that has the ability to stop a train if it violates a signal (runs a red light), by triggering an emergency brake application. This safety method is identical to that of the New York City Subway system. If a train is occupying a block, the two or more signals behind the train will be red, with the trip arms in the danger position so that another train cannot proceed into the area. The distance between