@stefanlindbohm In Poland, always use the train operator's brand - as I understand it, our law is kind of deficient when it comes to railway ticket integration and assumes the operator handles ticket issuance and passenger service, except in the case of 'municipal' railway operators, of which there is formally only one - SKM Warszawa. That one is fully integrated into Warsaw's urban network and uses their "WTP" ticketing and branding, although I don't think it's worth making an exception to the rule there. Elsewhere, there is no (and cannot be) fully integrated ticketing in the sense of the regional railway not issuing its own tickets at all, like you see in Germany or Sweden. The operator is always prominent, even where semi-integrated tariffs and (voivodeship-planned) networks do exist, especially if you're travelling on single tickets (such tariffs are handled by voivodeships contractually requiring operators to incorporate the tariff and any future changes into their own offer, where the voivodeship doesn't outright own the operator)

A branding quirk reflected in station announcements is that Polregio refers to its trains as REGIO, while voivodeship railways are best recognized under their own name, though for timetable purposes they use the generic "Osobowy" category. This is kind of like Sprinter vs Stoptrein in the Netherlands