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48 APM Performance Measures reporting form can be found in Data Requirements and Sources Exhibit A as Form B. The data and sources required to calculate Unintended Stops per 1,000 Interstations are provided in Table 21. 5.3.9Airport APM Performance Measure #7: Unintended Stops per 1,000 Interstations Collection Techniques and Calculating and Recording the Measure Unintended Stops per 1,000 Interstations is the rate at It is recommended that the collection of data for the Un which unintended stops have occurred outside of stations in intended Stops per 1,000 Interstations performance measure the airport APM system. It is defined as: be accomplished daily but be reported no more frequently than monthly since unintended stops in airport APM systems Monthly US1ki = (( m d =1 ) US 1, 000 ) may not occur frequently. In addition, the numeric value of d=1 I the measure, if reported daily, could be misinterpreted to be m high because the underlying basis is only 1 day's worth of inter- Yearly US1ki = (( y d =1 ) US 1, 000 ) stations traveled as opposed to 30 days' worth of interstations traveled in a monthly reported measure. d=1 I y For this measure, most of the data will typically be col- lected from records and systems in the control center. Where Where: the functionality of the CCCS and the specificity of the APM system output data allow, it may be possible to collect data for US1ki = Unintended Stops per 1,000 Interstations. the Unintended Stops per 1,000 Interstations performance US = Number of unintended stops. measure directly from the CCCS. In many cases, this allows Unintended stop is the stopping of an in-service train in a reports to be automatically generated directly by the CCCS. It location outside of a station where the train does not nor- is recommended that this process be instituted if the systems mally stop as part of the nominal system operation. and data will support it. I = Interstations. Interstations is defined as the total num- Other airport APM systems may have to rely on a process ber of interstations traveled by all in-service trains, with that is separate from the CCCS for this performance measure one interstation being the directional segment between and/or export and analysis of data from the CCCS. If this two adjacent stations in the system. For example, a train is the case, then it is recommended that the data required operating from stations A to D in Figure 6 would travel for this performance measure be manually or automatically two interstations (A to C and C to D); an in-service train collected daily and entered in a file of a spreadsheet application operating a round trip on a two-station shuttle system containing the necessary formulas and placeholders to calculate would travel two interstations. the measure. In-service train is a train located in the passenger-carrying To track performance over time, it is recommended that portion of the system that passengers are able to use for Unintended Stops per 1,000 Interstations be calculated for transport. the month and year, with those measures reported monthly d = Day of the month or year, as applicable. to the thousandths. The measure reported for the year is always m = Days in the month. cumulative-to-date, and it resets upon the start of the new year. y = Days in the year. For example, if the monthly report is being issued for the Table 21. Data requirements and sources, Airport APM Performance Measure #7: Unintended Stops per 1,000 Interstations. Data Requirement Source ATS, CCCS 1 Number of unintended stops Control center logbooks Incident reports Interstations, determined from origin terminal departure times, ATS, CCCS 2 by train number, and destination terminal arrival times, by train number, for example

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49 Table 22. Example Reporting of Airport APM Performance Measure #7: Unintended Stops per 1,000 Interstations. February 2010 Month Year-to-Date Unintended Stops per 0.003 0.002 1,000 Interstations month of February for a particular year, the reported monthly An example of how the Unintended Stops per 1,000 Inter measure would be for the entire month of February, and the stations performance measure could be reported for the month reported yearly measure would be the cumulative measure of of February 2010 is provided in Table 22, and the Airport Unintended Stops per 1,000 Interstations from January 1st APM Performance Measures reporting form can be found in through February 28th of that year. Exhibit A as Form B.