Issue description
New vehicles should take precedence over replacements, currently it is the other way around.
An upgrade pushes out the one currently being built and causes it to start all over again.
Upgrades should join the back of the queue.
I tested it a second time and the same thing happened.
No need for a save game imho
Reproduction steps
Have a Vehicle Depot 2 and build a new vehicle and queue a couple.
Before the first one is finished upgrade an existing vehicle.
The upgraded vehicle jumps in front of the one currently being made. the one that was being made has to start all over again.
Game version and build number
Update 1 0.5.1b (206)
Operating system
Windows