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A D To aid with the tracking and calculation of the measures, a
C
Microsoft Excel workbook file containing several spreadsheets
B
(one for each measure) has been provided and made available
Figure 6. Example for download at the summary page for ACRP Report 37A,
route structure on an which can be found at http://www.trb.org/Main/Blurbs/
airport APM system. 166387.aspx. The file allows the user to simply input daily data,
and the measures are automatically calculated for the day,
month-to-date, and year-to-date.
5.2.5 Headway in Maximum Service The forms provided in Exhibit A, which are to be used in
reporting the measures and descriptive characteristics dis-
Headway in Maximum Service is defined as the most fre-
cussed in Sections 5.1 and 5.2, have also been made available
quent headway operated in the system during the peak period
for download from the ACRP Report 37A summary page, and
of the day that maximum service is provided during the report-
can be completed electronically for easier distribution and
ing period, with headway being the elapsed time between the
tracking.
same part of consecutive, in-service trains operating in the same
All of the measures described in Table 4 should be imple-
direction on the same guideway.
mented. The airport APM performance measures are defined
For example, as described in Figure 6, if during maximum
in detail in the following sections, beginning with Airport APM
service trains operate on separate routes between terminals
Performance Measure #1, which includes three approaches for
A and D, between terminals B and D, and between terminals
determining Service Availability. The Tier A approach is the
C and D, the Headway in Maximum Service would occur on
least complex and least comprehensive of the three approaches,
the guideway with the most frequent headway, or between
whereas the Tier C approach is the most complex and most
terminals C and D.
comprehensive of the approaches.
Headway in Maximum Service excludes headways that
For Airport APM Performance Measure #1: Service Avail-
involve in-service vehicles used to address atypical, failure,
ability, choose only one of the three approaches described in
or special-event service during the reporting period.
Sections 5.3.1, 5.3.2, and 5.3.3.
5.3Airport APM 5.3.1Airport APM Performance Measure #1:
Performance Measures Service Availability (Tier A Approach)
Airport APM performance measures are the metrics used
5.3.1.1Definition
to track and compare the performance of airport APM sys-
tems as seen from the passengers' perspective. There are seven Service Availability (Tier A Approach) is the percent
recommended measures, described by title in Table 4, that are age of time service has been available on the airport APM
to be reported on Form B, which is provided in Exhibit A. system, as defined herein. Recognizing that headway regu-
For each measure in this section, the following is provided: larity is of significant importance to airport APM users,
Service Availability (Tier A Approach) is based largely on
· A definition, headway performance. In an effort to maintain the simplic-
· Data requirements and sources for the measure, and ity and usability of the measure, it deliberately does not
· Data collection techniques and the calculating and record- attempt to capture all system events that an airport APM
ing of the measure. user could perceive as a loss of availability. Service avail-
ability approaches in subsequent sections become more
comprehensive in nature by capturing a greater share of
Table 4. Airport APM performance measures. those events, and carry with them a greater level of sophis-
tication as well.
No. Title Service Availability (Tier A Approach) is defined as:
1 Service Availability (choose one of the three approaches below)
A Tier A Approach
B Tier B Approach AOT
Daily SA A = × 100
SOT
C Tier C Approach
2 Safety Incidents per 1,000 Vehicle Service Miles
3 O&M Expense per Vehicle Service Mile
4 Passenger Satisfaction
5 Actual and Scheduled Capacity (Peak Versus All Other) m AOT
6 Missed Stations per 1,000 Station Stops Monthly SA A = d=1 × 100
d=1 SOT
m
7 Unintended Braking Applications per 1,000 Interstations
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· Incomplete trip is the trip of an in-service train that fails to
y AOT
Yearly SA A = d=1 × 100 make a station stop on the scheduled route or that fails to
d=1 SOT
y
finish the trip on the scheduled route.
· On-time headway is a headway that does not exceed the
Where: scheduled headway by more than 20 sec.
·d = Day of the month or year, as applicable.
·SAA = Service Availability (Tier A Approach). ·m = Days in the month.
·AOT = Actual operating time. The total time, in seconds, ·y = Days in the year.
that the system was operating, calculated by subtracting
downtime from scheduled operating time (SOT D). Deliberately employing operating strategies to eliminate
·SOT = Scheduled operating time. The total time, in seconds, or stop the accumulation of downtime by exploiting the
that the system was scheduled to provide service. intent of the rules herein, especially when those strategies do
·D = Downtime. The total time, in seconds, of all downtime not benefit the APM user, is not permitted in the context of
events. this system of evaluation (e.g., using a schedule that provides
· A downtime event is any of the following: for less frequent scheduled headways than the actual service
When the actual headway of in-service trains exceeds the headways). Inserting additional trains to recover from a
downtime event is permitted, but operating additional trains
scheduled headway by more than 20 sec during the time
as a routine course over and above what the schedule requires
when the system is scheduled to provide service. This
is not. In such a case, the schedule should be modified to
downtime event begins at the departure time of the
reflect the actual operation.
in-service train that produced the last on-time head-
All downtime is to be quantified and assigned to one of the
way on the scheduled route before the event; it ends
following predefined causal categories:
at the departure time of the in-service train that pro-
duces the first on-time headway on the scheduled route
· Weather-induced. Downtime caused by the weather, such
after the event.
as lightning striking the guideway, or a snow or ice storm.
When any in-service train has an incomplete trip on
· Passenger-induced. Downtime caused by a passenger,
a scheduled route during the time when the system
such as a passenger holding the vehicle doors open or a
is scheduled to provide service. This downtime event
passenger pulling an emergency evacuation handle on an
begins at the departure time of the in-service train that in-service train.
produced the last on-time headway on the scheduled · System equipment-induced. Downtime caused by system
route before the departure time of the train having the equipment, such as a broken axle on an in-service train, or
incomplete trip; it ends at the departure time of the train control system equipment that fails while in service.
in-service train that produces the first on-time headway · Facilities-induced. Downtime caused by the facilities, such
on the scheduled route after the departure time of the as a station roof leaking water onto the floor immediately
train having the incomplete trip. in front of one side of the station sliding platform doors,
When the first daily departure of an in-service train requiring a bypass of that side of the station, or a crack in
from the terminal on each scheduled route fails to occur a guideway pier that limits the number of trains in an area.
within the time of one scheduled headway during the · Utility-induced. Downtime caused by a utility service pro-
time when the system is scheduled to provide service. vider, such as the loss of an incoming electrical feed to the
This downtime event begins at the scheduled opening APM system.
time and ends at the time of the first departure of an · O&M-induced. Downtime caused by personnel affiliated
in-service train from the terminal on the scheduled route. with the O&M organization, such as the mis-operation of
If any of these downtime events occur at the same time the system from the control center or the failure of a main-
or overlap one another, the earliest start time and the latest tenance technician to properly isolate a piece of equipment
end time of the events, as defined by the rules herein, are from the active system operation on which he or she is
to be used in determining downtime. working.
· Headway is the elapsed time between the same part of con- · Other. Downtime caused by other issues, such as a terrorist
secutive, in-service trains operating in the same direction threat or a delay due to the transport of a VIP.
on the same guideway.
· In-service train is a train located in the passenger-carrying There are no provisions for partial service credit in this
portion of the system that passengers are able to use for measure, no penalties for line capacity reductions (i.e., shorter
transport. trains), no allowances for grace periods (other than the 20-sec
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duration defined previously), and no penalties for unsched- of the causes of particular events, and perhaps not much
uled stops of trains outside stations. Nor are there exclusions more, depending on the sophistication of the CCCS and
for downtime events. This maintains the simplicity and output data generated by the airport APM system. Control
usability of the measure while providing a measure most center personnel usually perform these updates after each
reflective of the perspective of the airport APM user. downtime event or before their shifts are complete. In many
cases, this allows reports to be automatically generated (usually
daily, monthly, and/or yearly) directly by the CCCS. If this
5.3.1.2 Data Requirements and Sources
functionality exists within the CCCS, it is recommended that
The data and sources required to calculate Service Avail- it be used since it could save time and effort.
ability (Tier A Approach) are provided in Table 5. Some CCCSs do not have the capability described previ-
The location in the system where the departure times ously but instead can dump the raw output data acquired
will be used as the basis for calculating Service Availability from the airport APM system automatically to a batch file
(Tier A Approach) should be where the Headway in Maximum or to some other network location connected to the CCCS.
Service occurs, as defined in Section 4.2.5. It should specifically This is typically done at the end of the operating day or shortly
be at a terminal station, where possible. thereafter. In this case it may be easiest to import the data
into a spreadsheet application having a file specifically devel-
oped to calculate and track this performance measure. The
5.3.1.3Data Collection Techniques and Calculating
application and file could be installed on a personal computer
and Recording the Measure
in the control center so that staff there would have the same
It is recommended that the collection of data for the Ser- ability to keep the data current on each shift. It is assumed for
vice Availability (Tier A Approach) performance measure be the purpose of this guidebook and this performance measure
accomplished daily, since the measure will serve a useful pur- that airport APM systems at least have the capability to retrieve
pose in describing performance when reported daily within departure times (with train numbers), scheduled opening and
an organization. closing times, and incomplete trip information in an electronic
For this measure, most of the data will typically be col- file format from the CCCS.
lected from records and systems in the control center. In Regardless of how the data are collected, some manual
some cases, the control center computer system (CCCS) that updates will need to be undertaken in the application for each
is part of the ATS subsystem will have the functionality to downtime event to ensure that the measures are recorded and
allow user-defined reports and/or performance measures to reported accurately. Specifically, a cause for each downtime
be generated based on custom rules set by the user, and from event will need to be assigned. These causes are defined and
output data generated by the airport APM system itself. After discussed in Section 5.3.1.1. There can be one or more causes
the one-time setup of the performance measure in the CCCS, assigned to a single downtime event. For example, there may
most of what is needed thereafter are the incidental updates be one downtime event for the day, which was initially caused
Table 5. Data requirements and sources, Airport APM Performance
Measure #1: Service Availability (Tier A Approach).
Data
Requirement Source
Actual departure times, by train ATS subsystem of the ATC system; typically
number, of in-service trains from recorded by the control center computer system
1
the terminal station of each route (CCCS)
in the system
Scheduled headways, by period,
ATS, CCCS
2 and opening and closing times of
the system
Control center logbooks
Location, time, and train number Incident reports
3 of trains that fail to dwell at Work orders
stations on a scheduled route ATS, CCCS
Control center logbooks
Location, time, and train number
Incident reports
4 of trips not finished on a
Work orders
scheduled route
ATS, CCCS
Control center logbooks
5 Cause of downtime events Incident reports
Work orders
