Array Index Symptom 2

Article verified: February 2020

This is one cause of the Simulation error Array index is out of range error.

Symptom

You will see this error:

Simulation error: Array index is out of range.

In the log file, you'll see one of the following below the error:

at PassengerTrainAI.SimulationStep ...
or at PassengerTrainAI.StartPathFind ...
or something similar starting with at PassengerTrainAI
or at MetroOverhaul.Detours.PassengerTrainAIDetour.StartPathFind

Cause

This appears to be caused by the Metro Overhaul Mod.

WARNING: Don't just unsubscribe MOM; go through procedure in the Solution section first.

It appears that MOM is not correctly handling deletion of metro assets or routes (we don't know enough about MOM to say for sure). For background information, see Issue #82, also see Steam discussion.

Your log file might also include something like this:

at TrafficManager.Custom.AI.CustomTrainAI.CustomSimulationStep

While TrafficManager is mentioned in the extended error message, it's not the cause of the error, just affected by it.

Solution

Do NOT just unsubscribe MOM, as that will cause loads of other errors. The bullet points below suggest a way to recover from the error without unsubscribing. However, if you want to unsubscribe MOM, do it properly - see: How to remove workshop networks. Note that unsubscribing probably won't fix the error.

First, try this:

Subscribe and enable Loading Screen Mod (LSM)
In LSM mod options, enable the Safe Mode settings
Load your save
If it works, save under new name, exit game to desktop, then relaunch and it should be fine after that (until MOM breaks again)

If that doesn't work, however:

Enable Ghost Mode in MOM mod options
Load the save that has the problem
- All MOM stuff will be disabled due to Ghost Mode
Save the game under new name
Exit to desktop
Re-launch the game and load the newly created save

If that doesn't work: