Chapter 5: Workshop Configuration¶

File: workshops.json¶

The workshops.json file defines retrofit workshops, their capacity, and associated tracks. Workshops are the critical bottleneck in the simulation where wagons receive DAC retrofits.

Example Configuration¶

{
  "metadata": {
    "description": "Workshop configurations for DAC retrofit operations",
    "version": "1.0.0",
    "created": "2024-01-15"
  },
  "workshops": [
    {
      "id": "WS_01",
      "name": "First workshop",
      "retrofit_stations": 2,
      "track": "track_WS1"
    },
    {
      "id": "WS_02",
      "name": "Second workshop",
      "retrofit_stations": 2,
      "track": "track_WS2"
    }
  ]
}

Structure¶

Metadata¶

Optional metadata for documentation:

Parameter	Type	Description
`description`	string	Workshop configuration description
`version`	string	Configuration version
`created`	string	Creation date

Workshop Definitions¶

Each workshop in the workshops array:

Parameter	Type	Required	Description
`id`	string	Yes	Unique workshop identifier
`name`	string	No	Human-readable workshop name
`retrofit_stations`	integer	Yes	Number of parallel retrofit stations
`track`	string	Yes	Associated track ID from tracks.json

Parameters Explained¶

id¶

Unique identifier for the workshop:

"id": "WS_01"

Must be unique across all workshops
Used in logs and reports
Referenced internally by simulation

name¶

Human-readable workshop name:

"name": "First workshop"

Optional but recommended
Used in reports and visualizations
Helps identify workshops during analysis

retrofit_stations¶

Number of parallel retrofit stations in the workshop:

"retrofit_stations": 2

Critical Parameter: - Determines how many wagons can be retrofitted simultaneously - Directly affects workshop throughput - More stations = higher capacity but higher cost - This is the ONLY capacity constraint - track length is not checked

Throughput Calculation:

wagons_per_hour = (retrofit_stations * 60) / wagon_retrofit_time

Example: - 2 stations, 60-minute retrofit time - Throughput: (2 × 60) / 60 = 2 wagons/hour - Daily capacity: 2 × 24 = 48 wagons/day

Typical Values: - Small workshop: 1-2 stations - Medium workshop: 2-4 stations - Large workshop: 4-8 stations

track¶

Reference to the workshop track:

"track": "track_WS1"

Must match a track ID from tracks.json
Track must have type "workshop"
Track length does NOT affect capacity (only retrofit_stations matter)

Workshop Capacity Analysis¶

Station Count Impact¶

Stations	Wagons/Hour (60min retrofit)	Daily Capacity	Use Case
1	1	24	Small operations
2	2	48	Standard workshop
4	4	96	High-volume workshop
8	8	192	Industrial-scale

Important: The number of retrofit_stations is the ONLY capacity constraint. The simulation pulls exactly as many wagons from the retrofit staging track as there are available stations. Track length is not checked.

Common Modifications¶

Increasing Workshop Capacity¶

Add more retrofit stations:

{
  "id": "WS_01",
  "name": "First workshop - expanded",
  "retrofit_stations": 4,  // Was 2
  "track": "track_WS1"
}

Effect: - Doubles throughput - Reduces wagon waiting times - Processes 4 wagons simultaneously instead of 2

Adding a New Workshop¶

{
  "id": "WS_03",
  "name": "Third workshop",
  "retrofit_stations": 2,
  "track": "track_WS3"
}

Requirements: 1. Add edge in topology.json: "WS3": {"nodes": [1, 2], "length": 260.0} 2. Add track in tracks.json: {"id": "WS3", "edges": ["WS3"], "type": "workshop"} 3. Add routes connecting WS3 to other tracks in routes.json

Note: Track length can be any reasonable value - it doesn't affect workshop capacity. Only retrofit_stations determines how many wagons are processed simultaneously.

Effect: - Increases total retrofit capacity - Improves throughput - Reduces bottlenecks

Asymmetric Workshop Configuration¶

Different workshops with different capacities:

{
  "workshops": [
    {
      "id": "WS_01",
      "name": "Small workshop",
      "retrofit_stations": 1,
      "track": "track_WS1"
    },
    {
      "id": "WS_02",
      "name": "Large workshop",
      "retrofit_stations": 4,
      "track": "track_WS2"
    }
  ]
}

Use case: Modeling existing infrastructure with varying capacities

Workshop Selection Strategy¶

The workshop_selection_strategy in scenario.json determines how wagons are assigned to workshops:

least_occupied:

Workshop 1: 1/2 stations busy → 50% utilization
Workshop 2: 2/2 stations busy → 100% utilization
→ Wagon assigned to Workshop 1

first_available:

Workshop 1: 1/2 stations busy → available
Workshop 2: 2/2 stations busy → full
→ Wagon assigned to Workshop 1 (first with capacity)

Validation Rules¶

Workshop IDs must be unique
retrofit_stations must be positive integer
Referenced tracks must exist in tracks.json
Referenced tracks must have type "workshop"
At least one workshop must be defined

Effect on Simulation¶

retrofit_stations is the primary throughput determinant
Number of workshops provides redundancy and capacity
Track assignment affects spatial distribution
Workshop capacity often becomes the simulation bottleneck

Performance Considerations¶

Bottleneck Analysis¶

If workshops are the bottleneck: - Wagons queue at retrofit staging tracks - Parking tracks fill up - Collection tracks may block

Solutions: 1. Increase retrofit_stations in workshops.json 2. Add more workshops 3. Optimize workshop selection strategy

Capacity Planning¶

Rule of thumb:

required_stations = (total_wagons × wagon_retrofit_time) / (simulation_duration × 60)

Example: - 224 wagons - 60-minute retrofit time - 48-hour simulation (2880 minutes) - Required: (224 × 60) / 2880 = 4.67 → 5 stations minimum

ten_trains_two_days has 4 stations (2 workshops × 2 stations) → Expect some queuing

Next Steps¶

Continue to Chapter 6: Process Times Configuration to learn about operation durations.