# Defects

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## Operational Failures

These are defects involving rolling stock - things like locomotive power failures, defective brakes, and so on.

For each type, its chance of being chosen is defined only by the numerator. This makes it easier to add new failure types, as the chance of occurring is relative to the sum of all the other chances. The denominator, x, is the sum of all the numerators.

For example: if there are 9 failure types, and each has a 5/x chance of happening, then x is 45, and each chance is 5/45 or about 11%.

A second example: if one failure has a 10/x chance of happening, with the rest being 5/x, then the denominator is 50, so one failure has a 10/50 chance of happening, or about 20%, and the remaining 8 types have a 10% chance of happening.

When an irregularity type is chosen, the sim decides (pseudo-randomly) whether the failure will actually occur. If you imagine playing with a pair of dice, you can think of the sim making two rolls: first, to determine which type of failure to attempt, and a second roll, to determine whether the failure actually occurs. Below, the "relative chance of occurring" relates to the first roll of the dice. The second roll depends on the type of failure.

### FullPowerLoss

Relative chance of occurring: 5/x.

When this type of failure occurs, a random train has all of its traction power disabled for 1-6 minutes. Additionally, there is about a 60% chance that the train will momentarily cause the catenary system to be grounded (earthed) provided that the CaternaryExpert option is on, and the train is an electric train.

### PartialPowerLoss

Relative chance of occurring: 5/x.

When this type of failure occurs, a random train has some of its traction power disabled for 5-35 minutes. When accelerating, such a train will only accelerate about 25% of normal.

### CatenaryShortCut

Relative chance of occurring: 5/x.

The CatenaryExpert option needs to be enabled for this failure to happen.

When this failure occurs, a random catenary group that is not already earthed and is powered, will experience an earthing, followed by an unearthing. To reset, the dispatcher will need to reset any breakers that have tripped.

### DefectiveEmergencyBrake

Relative chance of occurring: 5/x.

When this happens, a random train experiences a sudden emergency brake application. When this happens, the driver will call the dispatcher to request a repair technician. Only when the repair is completed will the train resume. The time it takes for a train to be repaired is normally 2-5 minutes, but some layouts override these values, so in some yards, it can take a long time before a technician can travel to the affected train.

### PassengerEmergencyBrake

*Implemented in DEBUG only - needs some additional localisation work before it is ready.*

Relative chance of occurring: 5/x.

This failure happens when a passenger triggers the emergency brake.

### OverloadedTrain

*Implemented in DEBUG only.*

Relative chance of occurring: 5/x.

### LongPlatformStop

*Implemented in DEBUG only.*

Relative chance of occurring: 5/x.

### BlockedNeighbour

*Not currently implemented.*

Relative chance of occurring: 5/x.

### HotAxle

*Implemented in DEBUG only.*

Relative chance of occurring: 5/x.

## Infrastructure Failures

These are defects involving the railway infrastructure - things like signal lamps not working, switches not being thrown or not locking, and so on.

Just like for operational failures, each type of failure's chance of being chosen is defined only by the numerator value. The denominator, x, is the sum of all the numerators.

And, just like with the operational failures, there are two "rolls of the dice" - first to see which failure type will be attempted, and the second to see if it will actually happen. With this second roll, some types are more likely to happen under certain conditions. For example, switch obstructions are more likely when it's cold.

### SignalOneFilament

*Not Currently Implemented*.

Relative chance of occurring: 5/x.

### SignalAllFilaments

*Not Currently Implemented*.

Relative chance of occurring: 5/x.

### SwitchObstruction

Relative chance of occurring: 5/x.

When a switch obstruction occurs, about 5% of the time, it will be obstructed in both the normal and reverse positions. Otherwise, there's an equal probability that it's obstructed in the normal or reverse position. The probability that a switch obstruction is executed is doubled when it is cold.

To resolve, a technician must be called.

### SwitchDefectiveEndContact

Relative chance of occurring: 15/x.

When this type of failure occurs, about 5% of the time, it will be happen with both the normal and reverse end contacts. Otherwise, there's an equal probability that it's obstructed in the normal or reverse position.

To resolve, a technician must be called.

### SwitchOutOfCorrespondenceAfterTrain

*Not Currently Implemented*.

Relative chance of occurring: 5/x.

### LampIsDefective

*This failure only applies to the GRS-NX (Dutch) panels.*

Relative chance of occurring: 5/x.

This failure resolves itself automatically, between 30 minutes and 2 hours after it occurs.

### TrackOccupationSpontaneous

Relative chance of occurring: 5/x.

With this failure, a short cut is added to a track circuit, making it appear occupied when it is not. This failure resolves itself automatically after 2-10 minutes. This failure affects boundary tracks without axle counters.

### TrackOccupationAfterTrain

Relative chance of occurring: 5/x.

With this failure, a short cut is added to a track circuit, making it appear occupied when it is not. This failure only happens when a track is occupied by a train. The effect is that when a train leaves a track, it remains occupied. This failure resolves itself automatically after 2-10 minutes.

### ExitLockLightPersistence

*Not Currently Implemented*.

Relative chance of occurring: 5/x.

### CatenaryGroupFailure

Relative chance of occurring: 5/x.

This failure occurs in sims where the "CatenaryExpert" option is disabled, preventing the dispatcher manual control over catenary operations. The simulation must have catenary groups.

When this failure is scheduled to occur, a random catenary group will experience a failure - power will disappear for between 2-12 minutes.

### PanelLightDefect

Relative chance of occurring: 1/x.

This failure finds a random tile with a random bulb in that tile and makes it "burnt out". To resolve, the dispatcher must right-click on the tile to choose the option "Fix Light Bulb." This process, like in real life, takes some time.