As I pointed out in another thread, factories some time impose very low max transit limits.
The player may set a 100% loading limit that will never be reached and the convoy may wait forever there for loading.
However, the system never report this as an error and the player may be unaware that he is stuck in the trap for a long time.
The UI should be gentle like a British gentleman. I think Professor Layton will say so. I made that patch and went up to level 5. (I heard fanfare and my health became max)

It's kinda stuck, so it's displayed in orange. After waiting for 3 months, the bar color and display will change at the beginning of the month.
If it wait for 4 months, it will annoy you with a well-established message. After that, it spams every month at the beginning of month just like any other stuck.
Also I am confident that these English is bad. Therefore they need to be calibrated.
Vehicle %s wait loading too much!
Waiting too much for loading (%i->%i%%)!
I also recommend shortening it if possible.
github branch is here
https://github.com/Ranran-the-JuicyPork/simutrans-extended/tree/wait-loading-too-muchHope this patch saves the trapped player. Thank you. (´・ω・`)