Chapter 4: Track Configuration¶

File: tracks.json¶

The tracks.json file defines functional tracks by assigning types and properties to the physical edges defined in topology.json. Track types determine how the simulation uses each track.

Example Configuration¶

{
  "tracks": [
    {"id": "parking1", "name": "Parking track", "edges": ["parking1"], "type": "parking"},
    {"id": "collection1", "name": "Collection track", "edges": ["collection1"], "type": "collection"},
    {"id": "WS1", "edges": ["WS1"], "type": "workshop"},
    {"id": "loco_parking", "edges": ["loco_parking"], "type": "rescource_parking"},
    {"id": "Mainline", "name": "Mainline connecting yards", "edges": ["Mainline"], "type": "mainline"}
  ]
}

Track Structure¶

Each track definition contains:

Parameter	Type	Required	Description
`id`	string	Yes	Unique track identifier
`name`	string	No	Human-readable track name
`edges`	array[string]	Yes	List of edge IDs from topology.json
`type`	string	Yes	Track type (determines function)

Track Types¶

parking¶

Purpose: Store wagons waiting for retrofit or after completion

{"id": "parking1", "name": "Parking track", "edges": ["parking1"], "type": "parking"}

Characteristics: - Used for wagon storage - Capacity based on edge length - Selected by parking_selection_strategy - Multiple parking tracks improve throughput

In ten_trains_two_days: 15 parking tracks (parking1-parking16, excluding parking4)

collection¶

Purpose: Receive incoming trains and temporarily hold wagons

{"id": "collection1", "name": "Collection track", "edges": ["collection1"], "type": "collection"}

Characteristics: - First destination for arriving trains - Must accommodate full train lengths - Wagons are distributed from here to parking or retrofit - Typically 2-4 collection tracks needed

In ten_trains_two_days: 2 collection tracks

workshop¶

Purpose: Dedicated tracks for workshop operations

{"id": "WS1", "edges": ["WS1"], "type": "workshop"}

Characteristics: - Associated with workshop definitions in workshops.json - Wagons undergo retrofit here - Capacity affects workshop throughput - Number of tracks = number of workshops

In ten_trains_two_days: 2 workshop tracks (WS1, WS2)

retrofit¶

Purpose: Staging area for wagons ready for retrofit

{"id": "retrofit", "edges": ["retrofit"], "type": "retrofit"}

Characteristics: - Holds wagons waiting for workshop availability - Acts as a buffer between parking and workshop - Reduces workshop idle time

In ten_trains_two_days: 1 retrofit track

retrofitted¶

Purpose: Staging area for completed wagons

{"id": "retrofitted", "edges": ["retrofitted"], "type": "retrofitted"}

Characteristics: - Holds wagons after retrofit completion - Wagons distributed from here to final parking - Prevents workshop blocking

In ten_trains_two_days: 1 retrofitted track

rescource_parking¶

Purpose: Home location for locomotives and other resources

{"id": "loco_parking", "edges": ["loco_parking"], "type": "rescource_parking"}

Characteristics: - Locomotives return here when idle - Referenced in locomotive.json as "home track" - Typically one per locomotive

In ten_trains_two_days: 2 resource parking tracks

mainline¶

Purpose: Main circulation path connecting yard areas

{"id": "Mainline", "name": "Mainline connecting yards", "edges": ["Mainline"], "type": "mainline"}

Characteristics: - Used in route definitions - Represents main yard circulation - Not used for wagon storage - Typically very long

In ten_trains_two_days: 1 mainline track

Multi-Edge Tracks¶

Tracks can span multiple edges:

{"id": "long_track", "edges": ["edge1", "edge2", "edge3"], "type": "parking"}

Total length: Sum of all edge lengths Use case: Modeling tracks that span multiple physical segments

Track Naming¶

The name field is optional but recommended for clarity:

{"id": "parking1", "name": "North side parking track 1", "edges": ["parking1"], "type": "parking"}

Used in logs and reports
Helps identify tracks during analysis
Not used for simulation logic

Common Modifications¶

Adding More Parking Capacity¶

Add new parking tracks:

{"id": "parking17", "name": "Additional parking", "edges": ["parking17"], "type": "parking"},
{"id": "parking18", "name": "Additional parking", "edges": ["parking18"], "type": "parking"}

Effect: Increases total parking capacity, reduces waiting times

Adding Workshop Capacity¶

Add workshop tracks (must also update workshops.json):

{"id": "WS3", "edges": ["WS3"], "type": "workshop"}

Changing Track Type¶

Convert a parking track to collection:

{"id": "parking16", "name": "Converted to collection", "edges": ["parking16"], "type": "collection"}

Effect: Changes how the simulation uses this track

Validation Rules¶

Track IDs must be unique
All edge IDs must exist in topology.json
Track types must be valid values
Workshop tracks must have corresponding entries in workshops.json
Resource parking tracks must be referenced in locomotive.json

Effect on Simulation¶

Track type determines operational role
Number of tracks affects capacity and throughput
Track distribution impacts resource utilization
Edge references determine physical capacity

Track Type Summary¶

Type	Purpose	Typical Count	Capacity Impact
parking	Wagon storage	10-20	High - more = better throughput
collection	Train reception	2-4	Medium - must fit trains
workshop	Retrofit operations	1-3	Critical - bottleneck point
retrofit	Pre-workshop staging	1-2	Medium - buffer for workshops
retrofitted	Post-workshop staging	1-2	Medium - prevents blocking
rescource_parking	Locomotive home	1 per loco	Low - resource management
mainline	Circulation	1	Low - routing only

Next Steps¶

Continue to Chapter 5: Workshop Configuration to learn about workshop setup.