Great, thanks Misiek.
I've been relying on this site :
http://jareks.zonk.pl/signal/index.html since it's already in English. There are also a number of Polish sites, which Google translates badly. Marcin helps me understand things if Google does a really bad job.
For the main page though, I'd like to put images from in-game on there. So we'll slowly go through and take short clips of the blinking light signals and turn them into gifs (no idea how) for the website. They should also be 200x200 pixels in size.
I'm not sure which link you are referring to. The one in the dropdown on the main page has the link correct (your second one).
The 'Sz' (Sygnał zastępczy) translates to substituting signal according to the linked page
From what I understand, the signal is displayed when the train enters the station on the wrong track, or the other signals are broken, and they slow down to 40 km/h. Is this correct?
The SM42 will probably not have any more work done on it until Marcin starts working on the physics for diesel locomotives ( since they behave a bit differently). For now, I'm working on the EN57, and will post some screenies soon