I agree with @LarryD
Know that this way of running trains is a bit more dirt sensitive as one rail is not supporting the powering.
I run Marklin trains on K tracks and a signaling like Yours. I've used stuff from Littfinski Daten Technik. Unfortunately it looks like the old knowing owners sold their business to cashier only knowing people.
To the point. Their train indicating system uses opto couplers but sometimes extra pullups are needed. Don't underestimate how track length, length of the section, affects noise levels etc.
Make a principal drawing of the train presence detection You intend.