Here is the link to the screenshot of the rail (it is the first from the left, the one I have selected on "my hand"), thanks!
Minecraft says "Detector Rail" on it (creative mode). It is that one that activates red stone items near (including activator rails, which is my purpose, to set a direction for the tracks), when you have a cart over it 🙂
Thanks!
I found my way around it, thanks. I will just use regular powered rails connected to the detector rails instead, it works perfect as before! Thank you very much for your time!!