The interaction with trains is modeled with an event-based deleting and creating of doors. When a train arrives on the platform, doors are created and again deleting when the train departs.

## Train constraints

Information regarding trains are organized in two different files:

• Train timetable: This file defines arrival and departure times of trains.
• Train types: In this file types of trains are defined.

## Geometry definition

In order to process tracks correctly following constraints need to be respected.

### Constraints

Following constraints are to be respected when creating the geometry of a platform:

• Define a subroom of class Platform
• A Platform can have more than one track.
• A Platform is closed: Meaning it has whether transitions nor crossings except the platform accesses (e.g. stairs from the tunnel).
• tracks can be defined with walls of type track-n, where $n$ is the number of the track.

### Geometry sample

Following is an example of a platform with two tracks

 <room id="0" caption="station">
<subroom id="1" caption="dummy" class="Platform" A_x="0" B_y="0" C_z="0">
<polygon caption="wall" type="track-2">
<vertex px="0" py="0"/>
<vertex px="0" py="3"/>
</polygon>
<polygon caption="wall" type="track-2">
<vertex px="10" py="0"/>
<vertex px="10" py="3"/>
</polygon>
<polygon caption="wall" type="track-2">
<vertex px="0" py="0"/>
<vertex px="10" py="0"/>
</polygon>
<polygon caption="wall" type="track-1">
<vertex px="0" py="3"/>
<vertex px="2" py="4"/>
</polygon>
<polygon caption="wall" type="track-1">
<vertex px="7" py="4"/>
<vertex px="8.00377" py="3.79962"/>
</polygon>
<polygon caption="wall" type="track-1">
<vertex px="8.00377" py="3.79962"/>
<vertex px="9.00063" py="3.53957"/>
</polygon>
</subroom>
<crossings/>
</room>


## Train timetable

### Definition

In this file the following information regarding a train are defined:

• Track where the train arrives, defines through two points: start and end of the track.
• the start and end of the train. Trains are assumed to be linear, although tracks can have a curve.
• Times of arrival and departure.

### Sample

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<train_time_table>
<train id="1" type="RE" room_id="0"
track_start_x="-10" track_start_y="10"
track_end_x="0" track_end_y="10"
train_start_x="1" train_start_y="3"
train_end_x="7" train_end_y="3"
arrival_time="5" departure_time="15">
</train>
<train id="2" type="ICE" room_id="0"
track_start_x="0" track_start_y="10" track_end_x="10" track_end_y="10"
train_start_x="2" train_start_y="3"
train_end_x="12" train_end_y="3"
arrival_time="30" departure_time="50">
</train>
</train_time_table>


## Train types

### Definition

A train is defined through the following information:

• type (string): for example RE or ICE.
• length (int): length of the train
• capacity (int): maximal number of passengers
• doors: a list of doors. Every door is defined by a 2D point.

### Train example

 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<train_type>
<train type="RE" agents_max="10" length="5">
<door id="1">
<vertex px="0.5" py="0.0" />
<vertex px="2" py="0.0" />
</door>
<door id="2" outflow="3">
<vertex px="4" py="0.0" />
<vertex px="5" py="0.0" />
</door>
</train>
<train type="ICE" agents_max="800" length="4">
<door id="1">
<vertex px="1" py="0" />
<vertex px="2" py="0" />
</door>
<door id="2">
<vertex px="4" py="0" />
<vertex px="5" py="0" />
</door>
</train>
</train_type>


### Capacity of a train

The number of agents in a train is calculated every time step as the sum of all agents passing through the train’s doors.

When this number exceeds the agents_max parameter, all train’s doors are closed.

## Transformation of coordinates

While train’s coordinates are relative to the start if the track (track_start), Door’s coordinates are relative to the point train’s start (train_start) as defined in the Train timetable file.

Therefore, the global coordinates of the train’s door [A,B] is calculated as follows

## Algorithm

Given a platform with at least one track, the geometry will be changed every time a train arrives and leaves the platform.

This will be done by projecting the train’s doors on the track. With “projection” we mean along the orthogonal direction to the door.

Every projection point is mapped to the corresponding wall on the track.

 std::pair<Point, Wall >


Since every train’s door [A, B], corresponds to two intersection points [T1, T2] with pairs <T1, W1> and <T2, W2>, we have three cases:

• case 1: W1 == W2
• case 2: W1 and W2 share one point
• case 3: W1 and W2 are disjoint, meaning several track’s walls are between.

To remove the walls between the points T1 and T2, following actions are performed according to each case:

• Remove from the building walls with end points between T1 and T2
• Add to the building a new transition [T1, T2]. This transition will have an id starting from 10000. This number is incremented every time a new train transition is added.

• Add to the building new walls to close the gaps.

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