Is the correct signal displayed here? Do these two green lights mean that you can continue at maximum speed? After 900 meters, it turns out that you have to brake to 60 km/h because the track is changing.
Yes, those signals are correct. In the first image you see a Vr1 (expect drive) announcing the signal of the main signal (the signal on the top in the 2nd image). In the second image you can see a such called "Mehrabschnittssignal", a main signal also featuring a signal-announcer (Vr, the signal at the bottom). The main signal shows Hp1 (drive) and the signal announcer shows Vr2 (expect slow drive/40kmh unless specified otherwise by another signal). That means that at the next signal you are allowed to drive 40kmh (unless specified otherwise). Hope this clears some stuff up, feel free to ask questions.
At what speed can I pass the signal in the second photo? After 500 meters there is a switch with a speed limit. Why is Hp2 not displayed?
You can pass the signal with maximum speed as it is only announcing a Hp2. Though it is weird that there is no signal with Hp2. Is there a certain spot where the speed limit changes to 60, if so where is it?
There is no speed limit indicator between this signal and the railway switch. The track change occurs after 500 meters and the information about the limit refers to the next signal, at the exit from the station.