Pazoysky Yury Osharovich is the head of the
department «Railway stations and hubs» of Moscow State University of Railway
Engineering.
Shmal Vadim Nikolayevich is a senior
professor of the department « Management of operational work and safety on
transport» of Moscow State University of Railway Engineering.
Lanko Eugenia Vladimirovna is a student of
the department «The organization of transportation and management on transport
(railway transport)», Moscow State University of Railway Engineering.
Mathematical model
of the elimination of the conflicting routes of trains in a yard neck
Elimination
of the conflicting reception routes and departure routes (passing without
stopping) of a train in a yard neck is a mandatory requirement of train
protection at reception and departure of trains.
It is
offered to use a station model which consists of the following main components:
a yard neck (incoming routes and exit routes of the trains), station tracks,
open-line tracks. All these components are interconnected.
This
approach allows to pass from statics of an expert system to dynamics allowing
to receive the actual decision (the model exists in time) in any simulated
casual situation.
This model represents a problem of dynamic programming. With a certain
extent of specification, it allows to simulate work of a station on reception,
departure, shift of trains, closing of station tracks in connection with repair
work. The model is universal for terminus stations, side stations and
junctions.
Entrance
information of the model is:
- train arrival and departure time from station or shunting movement;
- minimum stopping time of trains at the stations;
- train number;
- number of open - line tracks from which the train arrives and on which
goes.
Output
information of the model is:
- train number;
- actual time of the train arrival and departure;
- actual stopping time of the train at the stations;
- delay time of train arrival and train departure;
- number of a station track on which the train arrives ;
- route of the train arrival and train departure.
The
interconnections of the components are presented as follows:
- number of station tracks and open-line tracks;
- the list of train arrival and departure routes (the route of reception
and departure of a train represents a station track),an open-line track (or the
first some block sections ) and a part of the yard neck connecting open-line
tracks and station tracks).
- number of approaches to a station (to each yard neck);
- connections of mutual influence between routes both in a yard neck,
and between yard necks which are presented in a table form of the route
dependence (this table defines the station scheme).
The condition of the components is presented as follows:
- the schedule of the train arrival and departure
at the station;
- occupation of the tracks by reception,
departure, passing of trains, in connection with repair work and for other
reasons;
- occupation of the reception routes and
departure routes of the trains;
- train priorities on arrival and departure;
- priorities of the reception routes and
departure routes of the trains;
- present moment of time.
Trains are compared on a total priority which is a sum of the following
priorities:
- route priority. Arrival routes and departure routes
are ranged depending on quantity of conflicts . The more the route causes
conflicts, the less its priority is.
Arrival routes and departure routes are ranged separately.
- train priority (depends on a category of a
train);
- an additional priority of a train according
to a dispatcher instruction (serves for direct control, which train to stop and
which train to send or to space);
- size of a departure priority over arrival
(shows to which extent an arrival priority is higher than a departure priority or
vice versa)
- priority of arrival sequence.
The size of the priorities is established in the course of the system
training. Priorities of the objects in group and between groups are adjusted.
Indignation entering from outdoor environment , an emergence check of
the conflicting routes of the train reception and departure is performed. In
case of conflict emergence, an alternative of their elimination with the
minimum sum temporary delays of train reception and train departure is
calculated.
The
calculation occurs for an interval which size is defined by accuracy of
entrance information.
1) Pre settlement
stage of initial information analysis.
For all
trains, the arrival or departure of which coincides with a settled interval of
time, the possibility of train occupation of the reception or departure route
is checked. There is a selection of all possible routes of reception/departure
of trains.
For
each route the list of all trains which submitted demands for departure and
(or) on arrival from station is formed.
Further
assessment of the route guidance is paid off for all trains and for all routes.
2) First
iteration.
Confirmation
of the train claim for a route is analyzed for each pair (a considered route
and a train).
Further
a pair with the maximum sum priority is chosen. The demand of a train to which
there corresponds this maximum value, is considered satisfied. The actual
departure/ arrival time of a train at a station is fixed.
If the
train arrived at the station, the appropriate station way becomes occupied. If
the train left the station, the mark on release of the appropriate way is made
as well as the mark that the appropriate boiling way or the first block section
is occupied or vacant.
3) Subsequent iterations (check of the possibility of the parallel train
reception or (and) parallel train departures).
After all iterations, for this moment of time, the satisfaction of all
demands for train arrival (departure) is analyzed. The size of a departure/
arrival time delay, equal to considered intervals of time is added to trains,
whose demands weren't satisfied.
If the train passes the station without stopping (duration of the
stopping is equal to zero), there is a check of both arrivals at the station,
and departures.
The accounting of a turn of passenger structures is possible. On the arrival
of a train at the station and stay at the station of the train turn time, the
train goes on a haul from which arrived and under a concrete train path.
The
model training paradigm represents supervisory learning. Within such approach
to the model the problem is set, and the decision on a known condition
"input-output" is looked for. The dispatcher specifies, what should
be the correct decision. That is, the operator specifies at the conflict
emergence, which train is necessary for accepting (or to send) and which train
is necessary to stop.
Learning
consists in correction of the train scales and train routes in such a manner
that at the next moment of time the exit calculation result of a network will
be closer to the demanded answer.
The
process of training is continuous (the database for possibility of a logic
conclusion is collected) as the external conditions defining entrance and exit
information, constantly change.
This
model is flexible and adaptive to changes of the situation. The decision
received with its help allows to facilitate essential problems of elimination
of the conflicting routes and to increase traffic safety, quality of passenger
service and efficiency of the use of railway transport technical means, taking
into account possibilities of railway station track arrangement. This model can
be used for automated management of train movement at a section.
Summary: the article
represents a mathematical model of the elimination of the conflicting routes in
a yard neck taking into account priorities of the trains and the minimum total
delays of the trains.
Keywords: mathematical
model, yard neck, route, traffic safety.