Not sure whether this problem is related to simutrans or to awesome window manager.
Sometimes keyboard shortcuts (e.g. 'p' for pause) don't work. If I change the layout of my desktop with Mod4 (windows key) + space, keyboard shortcuts work again. Haven't experienced such problems with any other programs I use under awesome.
I am running simutrans pak64 111.2.2, debian linux with awesome window manager.
Simutrans uses and SDL backend on Linux. Any keys are recieved via SDL; therefore such problems should occur with other games using the SDL library (which cover many of them).