selected train is not under user control

I was having fun running a bunch of consists in a test map. Suddenly, one of the consists could not be given driving instructions at the bottom of the Driving screen. The toggle to change control mode disappeared, replaced with the message "selected train is not under user control."

Any idea what could trigger this behaviour in TRS22 118660? Only one of the many consists on the map is affected by this.

It's normal if some asset like a passenger station has taken control of the train. Control is usally returned back to you once what ever it's doing (the script) completes. If this is not your case , disregard.

You'll also see that when an AI train is stopping or starting, and you attempt to take control. You need for the function to complete before you can do what you want.

This happens at the start of driving a route sometimes while the driver instructions are loading. As stated passenger stations and industry will take control of the train. Any other instructions may also control the train while that instruction is still active in the train's memory.

I believe you will also see this if loading is occuring at an industry and there is not enough product to satisfy the load request (amount). The train will be "under AI control" (automatic loading) forever if the industry doesn't make enough product.

There are no stations, or industries, only one very long loop with many signals to break it up into small blocks. While going through the list of drivers, I noticed one assigned to the lead engine of the consist not under my control. When I removed that driver, another driver took his place and I got control back. Now everything is fine again and the trains are moving.