Nice scenario!
PS - as author wrote - do not use ZEW randomly, because it will break signals. You have to use ZEW only once in this scenario, when you are explicitly instructed to by dispatcher. For other red signals just wait.
You also have to change cabs at Dąbrowa Górnicza Strzemieszyce and Włoszczowa Północ, but you are not instructed by text message (it is only noted in the timetable).
The scenario have included voice lines, but they will only play, if you have the game set to Polish.
The scenario unfortunately does not have any English translation. (There are only about 6 messages - search mission.lua for:
DisplayChatText
and
DisplayMessage
and use some translator, if you do not understand Polish. On lines: 85, 88, 179, 617+622, 626, 651, 813+814.)