Chapter 6: Process Times Configuration¶
File: process_times.json¶
The process_times.json file defines the duration of various operations in the simulation. These timing parameters directly affect throughput, resource utilization, and overall simulation performance.
Example Configuration¶
{
"wagon_retrofit_time": 60.0,
"train_to_hump_delay": 0.0,
"wagon_hump_interval": 0.0,
"screw_coupling_time": 3.0,
"screw_decoupling_time": 5.0,
"dac_coupling_time": 0.5,
"dac_decoupling_time": 0.5,
"brake_continuity_check_time": 0.5,
"full_brake_test_time": 4.0,
"technical_inspection_time": 2.0,
"shunting_preparation_time": 1.0
}
Parameters¶
All time values are in minutes unless otherwise specified.
wagon_retrofit_time¶
Time required to retrofit one wagon with DAC:
"wagon_retrofit_time": 60.0
| Value | Description | Throughput Impact |
|---|---|---|
| 30.0 | Fast retrofit (30 min) | High throughput |
| 60.0 | Standard retrofit (1 hour) | Medium throughput |
| 120.0 | Slow retrofit (2 hours) | Low throughput |
Critical Parameter: - Directly affects workshop throughput - Longer time = more bottlenecks - Shorter time = higher capacity requirements
Throughput Calculation:
wagons_per_station_per_day = (24 × 60) / wagon_retrofit_time
Examples: - 30 min: 48 wagons/station/day - 60 min: 24 wagons/station/day - 120 min: 12 wagons/station/day
Realistic Values: - Quick retrofit: 30-45 minutes - Standard retrofit: 60-90 minutes - Complex retrofit: 120-180 minutes
train_to_hump_delay (CNot fully implemented yet)¶
Delay before train wagons can be distributed:
"train_to_hump_delay": 0.0
Purpose: Models administrative or safety delays after train arrival
| Value | Description |
|---|---|
| 0.0 | Immediate processing (current setting) |
| 5.0 | 5-minute safety check |
| 15.0 | 15-minute inspection |
Effect: - Adds delay to all arriving trains - Increases collection track occupancy - May create arrival bottlenecks
Current Setting: 0.0 (no delay) for simplified simulation
wagon_hump_interval (Currently not fully implemented yet)¶
Time interval between distributing individual wagons:
"wagon_hump_interval": 0.0
Purpose: Models the time to separate and route individual wagons from a train
| Value | Description |
|---|---|
| 0.0 | Instant distribution (current setting) |
| 1.0 | 1 minute per wagon |
| 2.0 | 2 minutes per wagon |
Effect: - Longer interval = slower train processing - Affects collection track occupancy - Impacts locomotive utilization
Example: - 30-wagon train with 2-minute interval - Total distribution time: 30 × 2 = 60 minutes
Current Setting: 0.0 (instant) for simplified simulation
screw_coupling_time¶
Time to couple wagons using traditional screw couplers:
"screw_coupling_time": 3.0
Purpose: Models coupling wagons that haven't been retrofitted yet
| Value | Description |
|---|---|
| 2.0 | Fast coupling |
| 3.0 | Standard coupling (current) |
| 5.0 | Slow/careful coupling |
When Used: - Coupling non-retrofitted wagons - Initial train assembly - Moving wagons to retrofit
Realistic Values: 2-5 minutes per coupling operation
screw_decoupling_time¶
Time to decouple wagons using traditional screw couplers:
"screw_decoupling_time": 5.0
Purpose: Models decoupling wagons that haven't been retrofitted yet
| Value | Description |
|---|---|
| 3.0 | Fast decoupling |
| 5.0 | Standard decoupling (current) |
| 7.0 | Slow/careful decoupling |
When Used: - Separating non-retrofitted wagons - Train disassembly - Individual wagon movements
Note: Typically slower than coupling due to safety procedures
Realistic Values: 3-7 minutes per decoupling operation
dac_coupling_time¶
Time to couple wagons using Digital Automatic Couplers:
"dac_coupling_time": 0.5
Purpose: Models coupling retrofitted wagons with DAC
| Value | Description |
|---|---|
| 0.5 | Automatic coupling (current) |
| 1.0 | Semi-automatic |
When Used: - Coupling retrofitted wagons - Final train assembly - Moving completed wagons
Key Advantage: Much faster than screw coupling (0.5 vs 3.0 minutes)
Realistic Values: 0.5-1.0 minutes (automatic operation)
dac_decoupling_time¶
Time to decouple wagons using Digital Automatic Couplers:
"dac_decoupling_time": 0.5
Purpose: Models decoupling retrofitted wagons with DAC
| Value | Description |
|---|---|
| 0.5 | Automatic decoupling (current) |
| 1.0 | Semi-automatic |
When Used: - Separating retrofitted wagons - Parking operations - Final distribution
Key Advantage: Much faster than screw decoupling (0.5 vs 5.0 minutes)
Realistic Values: 0.5-1.0 minutes (automatic operation)
brake_continuity_check_time¶
Time for brake continuity check after coupling rake:
"brake_continuity_check_time": 0.5
Purpose: Safety check to ensure brake system is connected through all wagons
| Value | Description |
|---|---|
| 0.5 | Quick check (30 seconds) |
| 1.0 | Standard check (1 minute) |
| 2.0 | Thorough check (2 minutes) |
When Used: - After coupling wagons into a rake - Before train movement - Safety validation
Realistic Values: 0.5-2.0 minutes
full_brake_test_time¶
Time for full brake test on completed train:
"full_brake_test_time": 4.0
Purpose: Complete brake system test before mainline movement
| Value | Description |
|---|---|
| 3.0 | Quick test |
| 4.0 | Standard test (current) |
| 6.0 | Thorough test |
When Used: - Before mainline transport (collection → retrofit) - Before parking transport (retrofitted → parking) - Required for MAINLINE route type
Note: More comprehensive than brake continuity check
Realistic Values: 3-6 minutes
technical_inspection_time¶
Time for technical inspection of assembled train:
"technical_inspection_time": 2.0
Purpose: Visual and technical inspection before departure
| Value | Description |
|---|---|
| 1.0 | Quick inspection |
| 2.0 | Standard inspection (current) |
| 5.0 | Detailed inspection |
When Used: - Before mainline transport - After train assembly - Safety validation
Realistic Values: 1-5 minutes
shunting_preparation_time¶
Time for shunting preparation (safety checks, communication):
"shunting_preparation_time": 1.0
Purpose: Preparation time before locomotive movement
| Value | Description |
|---|---|
| 0.5 | Minimal preparation |
| 1.0 | Standard preparation (current) |
| 2.0 | Careful preparation |
When Used: - Before every locomotive movement - Safety communication - Route clearance
Includes: - Radio communication - Route verification - Safety checks
Realistic Values: 0.5-2.0 minutes
Coupling/Decoupling Comparison¶
| Operation | Screw Coupler | DAC | Time Savings |
|---|---|---|---|
| Coupling | 3.0 min | 0.5 min | 83% faster |
| Decoupling | 5.0 min | 0.5 min | 90% faster |
| Round trip | 8.0 min | 1.0 min | 87.5% faster |
Simulation Impact: DAC significantly reduces shunting operation time
Common Modifications¶
Faster Retrofit Operations¶
Simulate improved workshop efficiency:
{
"wagon_retrofit_time": 45.0,
"screw_coupling_time": 2.5,
"screw_decoupling_time": 4.0,
"brake_continuity_check_time": 0.5,
"technical_inspection_time": 1.5,
"shunting_preparation_time": 0.5
}
Effect: - Increases throughput by 25% - Reduces workshop bottlenecks - Improves resource utilization
Realistic Train Processing¶
Add delays for safety and inspection:
{
"train_to_hump_delay": 10.0,
"wagon_hump_interval": 1.5,
"brake_continuity_check_time": 1.0,
"full_brake_test_time": 5.0,
"technical_inspection_time": 3.0,
"shunting_preparation_time": 1.5
}
Effect: - More realistic simulation - Increases collection track occupancy - May reveal arrival bottlenecks
Slower Coupling Operations¶
Model less experienced crews:
{
"screw_coupling_time": 5.0, // Was 3.0
"screw_decoupling_time": 7.0, // Was 5.0
"dac_coupling_time": 1.0, // Was 0.5
"dac_decoupling_time": 1.0 // Was 0.5
}
Effect: - Increases locomotive utilization - Longer wagon movement times - May create shunting bottlenecks
Validation Rules¶
- All values must be non-negative numbers
- Time values are in minutes
- Zero values are allowed (instant operations)
- Decoupling typically ≥ coupling time
Effect on Simulation¶
Primary Bottleneck: wagon_retrofit_time¶
This parameter typically dominates simulation performance:
Total retrofit time = wagon_count × wagon_retrofit_time / retrofit_stations
Example (ten_trains_two_days): - 224 wagons × 60 minutes / 4 stations = 3,360 minutes = 56 hours
Secondary Impact: Coupling/Decoupling¶
Affects locomotive utilization and wagon movement:
Movement time = travel_time + coupling_time + decoupling_time
Example: - Travel: 1 minute - Screw decouple: 5 minutes - Screw couple: 3 minutes - Total: 9 minutes per movement
Optimization Strategy¶
- Reduce retrofit time → Biggest throughput impact
- Optimize coupling operations → Improves shunting efficiency
- Minimize delays → Reduces idle time
- Balance all parameters → Realistic simulation
Performance Tuning¶
High Throughput Scenario¶
{
"wagon_retrofit_time": 30.0,
"train_to_hump_delay": 0.0,
"wagon_hump_interval": 0.0,
"screw_coupling_time": 2.0,
"screw_decoupling_time": 3.0,
"dac_coupling_time": 0.5,
"dac_decoupling_time": 0.5,
"brake_continuity_check_time": 0.5,
"full_brake_test_time": 3.0,
"technical_inspection_time": 1.0,
"shunting_preparation_time": 0.5
}
Realistic Scenario¶
{
"wagon_retrofit_time": 75.0,
"train_to_hump_delay": 15.0,
"wagon_hump_interval": 2.0,
"screw_coupling_time": 4.0,
"screw_decoupling_time": 6.0,
"dac_coupling_time": 1.0,
"dac_decoupling_time": 1.0,
"brake_continuity_check_time": 1.0,
"full_brake_test_time": 5.0,
"technical_inspection_time": 3.0,
"shunting_preparation_time": 1.5
}
Conservative Scenario¶
{
"wagon_retrofit_time": 120.0,
"train_to_hump_delay": 20.0,
"wagon_hump_interval": 3.0,
"screw_coupling_time": 5.0,
"screw_decoupling_time": 7.0,
"dac_coupling_time": 1.5,
"dac_decoupling_time": 1.5,
"brake_continuity_check_time": 1.5,
"full_brake_test_time": 6.0,
"technical_inspection_time": 5.0,
"shunting_preparation_time": 2.0
}
Next Steps¶
Continue to Chapter 7: Locomotive Configuration to learn about shunting resources.