# Analyzing Railroad Dispatchers' Strategies:

# A Cognitive Task Analysis of A Distributed Team Planning Task

Emilie M. Roth

Roth Cognitive Engineering

Brookline, MA 02146

Nicolas Malsch

Human-Machine Systems Lab

Massachusetts Institute of Technology

Cambridge, MA 02139

Jordan Multer, Michael Coplen, Nora Katz-Rhoads

Volpe National Transportation Systems Center

Cambridge, MA 02142

# ABSTRACT

This paper describes a preliminary cognitive task analysis (CTA) that is
being conducted to examine how experienced train dispatchers manage and
schedule trains. The CTA uses ethnographic field observations and
structured interview techniques. The objective is to gain insight into
the cognitive demands placed on train dispatchers and the strategies
they have developed in response to those demands, as an input to guide
development and design of digital communication systems and advanced
information displays.

The paper reports selected results of the CTA that reveal some of the
complexities faced by train dispatchers and the cognitive and
collaborative strategies they have developed in response to those
demands. The results of the preliminary CTA reveal that dispatchers have
developed a variety of strategies that smooth the way for trains to pass
through territories safely and efficiently and satisfy the multiple
demands placed on track use. In many cases these strategies depend on
communication and coordination among individuals distributed across time
and space. A core basis for coordination is the use of radio as a
communication device that provides for a shared frame of reference. The
ability to overhear communications directed at others that have a
bearing on achievement of your own goals and to recognize when
information in your possession is of relevance to others and broadcast
it, are important contributors to efficient management of track use.
Dispatchers' planning and scheduling is proactive, anticipatory and
opportunistic -- taking advantage of windows of opportunities that arise
to satisfy the multiple demands that are placed on track use. The
results have implications for training and the application of advanced
display and communication technologies to improve train routing safety
and efficiency.

# INTRODUCTION

As part of it\'s efforts to investigate the safety implications of
applying emerging technologies to railroad operations the Federal Rail
Administration\'s Office of Research and Development is sponsoring a
cognitive task analysis (CTA) of railroad dispatcher\'s activities. This
CTA will be used to understand the implications of the adoption of
\"data link\" type communication systems to the railroad environment.
While data link has the potential to increase safety, and improve
productivity and efficiency of railroad operations, it is important to
clearly understand how this technology can affect human performance.

The purpose of the CTA is to examine how experienced train dispatchers
manage and schedule trains in today's environment. The objective is to
gain insight into the cognitive demands placed on train dispatchers and
the strategies they have developed in response to those demands as input
to guide the development and design of "data link" digital communication
systems and advanced information displays. The intent is to identify (1)
cognitive activities that could be more effectively supported through
the introduction of new technology as well as (2) features of the
existing environment that contribute to effective performance that
should be preserved when transitioning to new technologies.

Train dispatching is an example of a distributed team planning task in
that it requires communication and coordination among multiple
individuals who vary in scope of responsibility, task focus, and access
to information \[1\]. In the dispatch center we are studying there are 7
dispatchers working in parallel, each responsible for different
territories, who must coordinate with each other to optimize on-time
train performance.They must also communicate and coordinate with train
engineers, train masters, and track maintenance workers, each with
different performance objectives and access to different information
relevant to track management decisions.

This paper reports results from a preliminary CTA that was conducted to
gain an overview of dispatcher decision-making activities, sources of
complexity, and the knowledge and skills that underlie dispatching
expertise. The objective was to identify opportunities for improvement
in performance via changes in training, practice or introduction of new
technology. A particular focus was on characterizing current
communication practice between train dispatchers and other personnel
that impact train routing decisions (e.g., train engineers, train
conductors, maintenance of way personnel, chief dispatcher) as input to
development of new concepts for off-loading radio-based communication on
to alternative media (e.g., computer-based data link communication).

This paper reports selected results of the CTA that reveal some of the
complexities faced by train dispatchers and the cognitive and
collaborative strategies they have developed in response to those
demands. Specifically the paper focuses on strategies experienced
dispatchers have developed to anticipate and plan for future demands on
the track they control.

# METHODS

The preliminary CTA used a hybrid methodology \[2\] that combines
ethnographic field observations \[3\] with a structured interview
technique \[2,4\] to build and progressively grow and refine an
understanding of the demands placed on train dispatchers and the
knowledge and strategies that experienced dispatchers have developed to
respond to those demands.

The CTA began with two days of observations of train dispatchers as they
went about their job in their actual work environment in a train
dispatch center. Two observers, the first two authors, participated.
Each observer sat next to a train dispatcher and observed the
communications he or she engaged in, and the train routing and track
management decisions made. The observer asked the dispatchers questions
when invited to by the dispatcher during low workload periods. Questions
were guided by a checklist of topics to be covered that was generated
ahead of time. Observations were conducted across two shifts so that a
total of 8 dispatchers were observed. Observations included shift
turnovers.

Based on the results of the preliminary field observations a set of
questions were prepared to guide more in-depth structured interviews.
Three dispatchers were interviewed one at a time using a structured
interview form. The two observers who conducted the field observations
participated in the interviews. Interview topics covered included:

**· **Complicating factors that made track management and train routing
difficult;

**· **The strategies that they have developed to facilitate performance
and maintain the big picture;

**· **The communication systems and how they used them;

**· **Issues in training new dispatchers

**· **Suggestions for improved communication systems and/or computerized
support systems.

The interviews lasted approximately two hours and were audio-taped.

In addition to field observations and interviews of train dispatchers,
an interview was conducted with a commuter train engineer. The interview
was conducted in the engine cab during a scheduled run. The objective
was to examine the radio communication and train routing decision from
the perspective of the train engineer to look for convergence and/or
divergence of beliefs and opinions.

# RESULTS

**The Train Dispatching Environment**

The dispatch center we observed handles a mixture of long distance
passenger trains, local commuter trains, freight traffic and special
trains (e.g., private trains).

The dispatch center has 7 dispatchers working in parallel, each
responsible for different adjoining territories. The dispatchers each
sit at their own workstation in one large room. Dispatchers can talk
directly with those immediately around them (i.e., the dispatcher next
to them, in front or back). They can also talk with any dispatcher in
the room using an intercom system that they can access through their
phone handset.

Each dispatcher has four video display terminals at his own workstation.
One is devoted to display of radio and phone communication information.
Three are devoted to display of train information. Two of these are used
to show schematics of portions of the track. They are typically used to
display portions of the territory being controlled by the dispatcher.
The third is devoted to tabular/textual displays of information related
to train statuses. There is also a PC at each desk used for
administrative tasks.

There is also a large wall projected overview display that displays a
schematic of the entire set of railroad tracks being controlled from
that dispatch center. All the dispatchers can see the wall panel
overview display from their own workstation to get an overview of track
usage and train activity throughout the rail system being controlled by
that dispatch center.

Dispatchers' primary means of monitoring activity and communicating with
people in the field (i.e., train engineers, maintenance of way
personnel, train masters) is via a radio system. Dispatchers
continuously monitor the road channel that covers communication in their
territory and broadcast messages over the radio. They also have
available a phone that they occasionally use for one-to-one conversation
with people in the field (e.g., maintenance of way foremen, train
masters.)

**What Makes Train Dispatching Difficult?**

Routing trains that arrive on schedule is not hard. The tracks to be
used, and the meets (the time and place when two trains will meet) are
predefined and routing decisions are routine.

What makes dispatching hard is dealing with *unplanned demands* on track
usage, and the need for dynamic *re-planning* in response to train
delays, and track outages.

One source of complication is the need to satisfy the multiple demands
placed on track usage introduced by unanticipated requests for track use
while still insuring that scheduled trains are not delayed. Unplanned
(and thus unpredictable) demands on track usage include:

· maintenance of way (MOW) personnel requesting time to inspect and
maintain tracks;

· Freight trains that do not have precise schedules;

· Special trains (e.g., private trains).

Dispatchers must estimate the time required by these unplanned
activities and the time available before the track will be required for
a scheduled train. Often the demands placed on track use are greater
than can be satisfied at given point in time, requiring the dispatcher
to prioritize and perform triage (determine which activities/trains will
be delayed).

A second source of complexity is that trains are often delayed and/or
tracks are taken out of service making the preplanned routes and meets
obsolete, and necessitating dynamic re-computation of feasible train
routes and meets.

A third source of complexity is heavy attention and communication
demands, particularly over the radio. One dispatcher estimated 178
communications in one 8 hour shift (i.e., more than one every three
minutes). Communications include the need to:

· Answer requests for, and issue train movement and track usage
authorization to train engineers, MOW staff, etc.;

· Inform train engineers whether there are any updates to speed
bulletins or other messages;

· Find out the status of trains -- where they are, why they are delayed;

· Exchange information regarding rail conditions (e.g., broken rail;
malfunctioning signals; obstacles on the track; trespassers);

· Coordinate with train masters and yard masters;

· Coordinate with emergency response personnel (e.g., police, fire,
ambulance) in accident situations.

#### Typically, while the dispatcher is attending to one request, multiple other calls will come in on the radio. Per necessity, these calls get delayed in being answered.

A fourth source of complexity is the physical constraints that determine
under what conditions a train may proceed. The make up of the train and
physical characteristics of the track (i.e. track characteristics that
determine allowable speed, height of bridges over track that determines
maximum car height, hazardous materials in the rail car that may travel
through heavily populated areas) interact to affect the conditions under
which a train may move over specified sections of track. The dispatcher
must possess knowledge about the track that remains relatively stable
and information about the make-up of the train consist which may change
constantly as the train proceeds on its journey.

## Expert Strategies to Meet the Multiple Demands on Track Use

Dispatchers have developed a number of strategies that smooth the way
for trains to pass through territories more efficiently, and satisfy the
multiple demands that are placed on track use. Experienced dispatchers
have developed strategies that allow them to anticipate requirements for
changes to schedules and planned meets early so as to have time to take
compensatory action. They monitor the wall panel display, consult with
other dispatchers, and 'listen for' information on the radio that will
allow them to track progress of train movement and get early indication
of need for re-planning.

### Anticipate and Plan Ahead

Dispatchers have developed strategies to extract information from radio
communication and/or actively seek information to allow them to
anticipate delays and plan ahead. They actively monitor how the trains
that are headed their way are running. If a train is one hour late out
of the Boston terminal, they want to know right away. They also take
into account whether there is any slack in the train's schedule to
estimate whether the train is likely to make up any of the delay before
it reaches their territory. In the words of one dispatcher the ability
to anticipate and plan ahead is critical "otherwise you start getting
trains late and things start to get out of sync."

*Taking Advantage of the Radio "Party Line" Feature to Anticipate and
Plan Ahead*

Dispatchers routinely "listen for" information on the radio channel that
is not directly addressed to them but provides important clues to
potential delays, problems or need for assistance. As one dispatcher put
it "after a while you kind of fine tune your ear to pick up certain key
things". Examples include:

· *Identifying when a train has left a station*: The train conductor
will generally tell the engineer "OK out of New London", by comparing
the time to the scheduled departure you can compute the delay.

· *Identifying equipment problems: * By overhearing conversation between
a train engineer and the mechanical department, the dispatcher gets
early notice of malfunctioning train engines that will need to be
replaced. In one recent case there was a train with 500 or 600 people on
it and a malfunctioning engine. The dispatcher had overheard the
Engineer call the mechanical department and so began thinking about his
options and anticipated the need to hold another train back for two
minutes in order to minimize the delay of the train with malfunctioning
engine.

· *Listening for/heading off potential interactions and conflicts:
*Dispatchers listen for commitments made by others that may impact
activity in their territory. As example a train may request approval
from the dispatcher of an abutting territory to go toward his territory,
while the dispatcher may have already given someone else approval to
move on the same track in the opposite direction. It's important for the
dispatcher to catch that. In the words of one dispatcher "I have to make
sure that I remember each thing -- because if I send one guy toward the
yard and another out -- now you have two trains looking at each other
and they can't move -- You can get yourself stuck -- so it is important
to listen ahead."

The ability to listen ahead allows dispatchers to nip potential
conflicts before they arise. In one case a dispatcher overheard a
request made by a train to a tower to come out of the yard. In his words
"I know when someone is talking to South Bay tower, I know that sure
enough South Bay is going to talk to me and I'm going to have to do
something about it. So it is anticipation. Getting ready ahead of time.
Who can go when? Do I want to let him go now? Can the terminal
dispatcher handle him now?" He checked with the terminal dispatcher, who
was unable to take the train. He then called the tower to ask them to
delay the train -- all without ever having explicitly been asked.

· *Listening for mistakes.* An experienced train dispatcher will pick up
key information that may signal a misunderstanding, confusion, or error.
A case in point is a situation where a MOW person is working on the
wrong track. On the rail, it is easy for a MOW person, especially an
inexperienced one to get disoriented and think they are working on one
track when they are working on another. In one case a dispatcher
overheard a flagman talking to his crew say "OK to come out of the lot
at Endels". Endels was across the other side of live track, it was not
the track the MOW flagman had requested to be blocked off and protected.
The dispatcher immediately put signals to stop and called the MOW person
to alert him.

*Thinking Ahead/Cooperative Planning to Facilitate Train Movement Across
Territories*

Dispatchers have developed cooperative strategies to provide each other
with look ahead, and facilitate routing beyond their own territory. They
provide each other with status updates to support anticipation, they
consult with each other when there are alternative routing options that
may differentially impact the abutting dispatcher's territory, and they
try to accommodate each other. Dispatchers will:

· inform the adjoining dispatcher what track he is sending a train on
(or will ask which track he/she wants it on) so that the dispatcher
knows which track to expect a train on and therefore what signal
switching will be needed (e.g., when going from two tracks to one
track).

· alert abutting territory dispatchers that there will be a change in
the order in which trains will come into their territory (which may
trigger re-planning of routes and meets); or in cases where there is a
choice, will ask the dispatcher of the abutting territory which he/she
wants first. If one train will need to turn around right away, the
dispatcher will want that train first.

*Increasing Communication Efficiency: Cooperative Strategies Between
Dispatchers and Engineers *

Dispatchers and train engineers also act cooperatively and proactively
to increase communication efficiency between them, and facilitate train
movement. As example, train engineers are required to check with the
dispatcher for messages before leaving a train station. If a dispatcher
has the time, he will call the train engineer before he reaches the
station to let him know that there are no messages, and that he can
leave the station whenever he is ready. This will allow the train
engineer to start the trip back in the other direction more quickly.

In turn, train engineers will sometimes act proactively to save the
dispatcher time. For example, if a dispatcher sends a message over the
radio directed at one train engineer, but it is also relevant to others,
the others will call in over the radio acknowledging receipt of the
message (e.g., "This is 601, I copied that"). This eliminates the need
for the dispatchers to call them individually.

*Strategies to Take Advantage of Windows of Opportunity*

· Dispatchers will act pro-actively to take advantage of windows of
opportunity that open up. For example, if a dispatcher knows that a MOW
person needs some foul time (time during which track is taken out of
service for use by MOW workers), and he sees a window of opportunity, he
will call the maintenance of way person and offer some time. In one
case, as a second example, a passenger train was delayed (held up in the
adjacent territory). The dispatcher used the opportunity to tell a
freight train that he could pass through, given that the window of
opportunity had opened up.

### Strategies to Level Workload

Dispatchers work under externally-paced, high attention demand
conditions. Dispatchers have developed strategies to shift workload when
possible from high demand periods to lower workload periods. As example
they have learned to begin paper-work and book-keeping duties during low
workload period so as to avoid introducing workload bottlenecks later.
Examples include:

· *pre-naming a train* (i.e., entering it into the computer) before it
enters the system to save time later. (Note - if there is a change in
the expected order trains are inserted this will create more work rather
than less)

· *Clearing routes/setting blocks in anticipation of needs*. As example,
a dispatcher anticipated that a track car working on a stretch of rail
would need to request a an adjacent segment of track to be blocked off
next, so the dispatcher put in the block before getting the call from
the track car. As with other anticipatory strategies it can result in
delays if unanticipated conditions arise (e.g., trains/track cars come
through in a different order than anticipated).

· *Giving 'provisional authority'*. When someone comes in requesting a
stretch of track to be blocked and the dispatcher determines that
authority cannot be provided at that point in time but can be provided
once certain conditions are met (e.g., a train gets through), the
dispatcher can give provisional authority \-\-- authority that goes into
effect once specific conditions are met. He can begin the paper work on
his side and have the train engineer do the same, leaving the time the
authorization is to go into effect blank. Later when the conditions for
the authorization have been met, the dispatcher can call the person back
and indicate that the authorization is now in effect. This saves time,
and serves to level the workload since much of the paper-work is done at
a time when workload is not too heavy, rather than later when it could
be heavier.

Other related strategies to cope with high workload include:

· giving MOW foremen as much track as can be afforded all at once rather
than in stages to avoid having to issue repeated track use authorization
forms.

· Giving authorization for track usage "until further notice" rather
than for a fixed length of time, so that if the MOW needs more time than
anticipated and the time is available (e.g., there is no train that
needs the track) the MOW can use the extra time without requiring
additional paper work.

# DISCUSSION

The selected results of the CTA presented in this paper reveal that
dispatchers have developed a variety of strategies that smooth the way
for trains to pass through territories safely and efficiently and
satisfy the multiple demands placed on track use. These strategies
depend heavily on communication and coordination among individuals
distributed across time and space. One basis for coordination is the use
of radio as a communication device that provides for a shared frame of
reference. The ability to "listen in" on communications directed at
others that have a bearing on achievement of your own goals and to
recognize when information in your possession is of relevance to others
and broadcast it, are important contributors to efficient management of
track use. Dispatchers' planning and scheduling is proactive,
anticipatory and opportunistic -- taking advantage of windows of
opportunities that arise to satisfy the multiple demands that are placed
on track use.

The results have a number of implications for selection and training of
dispatchers and the application of technologies such as advanced
computer displays, decision support systems, and data link communication
to improve train routing safety and efficiency \[5, 6\]. The results
emphasize the skills that dispatchers have developed that allow them to
anticipate demands on track use and act proactively; plan cooperatively
across territory boundaries; and manage workload. These are important
cognitive skills that need extensive practice to develop. The results
also reveal the importance of the "broadcast/party line" aspect of radio
communication that provides a shared frame of reference and allows
dispatchers and others working on the railroad anticipate situations and
act proactively. Careful attention should be paid to preserving this
critical feature of radio communication in attempts to off-load radio
communication to other media \[7, 8\].

The results also contribute to the broader understanding of team
cognition in complex dynamic tasks that require communication and
coordination among multiple individuals distributed in time and space
\[9\].

**ACKNOWLEDGEMENTS**

This work was sponsored by the Federal Railroad Administration, Office
of Research and Development. The work was performed as part of a
collaborative effort between the Volpe National Transportation Systems
Center and MIT.

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