In Wykno station, a part of LCS Skrzynki scenery, there is a 40 km/h speed limit because of bad condition of the tracks. You probably didn't notice a triangular white sign with a black "4" digit on it, what informs you about the limit. The limited speed segment starts with a W9 sign (a rectangular white sign with a black arrow) with arrow facing downwards, and ends with a W9 with arrow facing upwards. You should carefully watch the tracks in front of your train
I also advice you to carefully read Ie-1 signalling instruction to know all signals and signs.
So, when you see this W8 triangular sign with a number, you should reduce your speed to this number multiplied by 10 km/h (for example, you see number 4 on the sign, sp you start braking to reduce your speed to 40 km/h)
Tip:when you drive through an offline scenery, you have to click f5 or type /zew1 to enable virtual dispatcher, so you won't have to drive through S1 signals, but remember that you still must ask the next dispacher via /swdr.