I think it will be left preserved and therefore not have a journey mode. To be honest, I hardly used journey mode in TSW2020. In TSW2, I did decide to make use of journey mode to experience a curated set of routes and preset weather conditions. It is something I'll be using throughout TSW2 now on all the routes that support it.
Of course, I love rapid transit particularly with the BR182, hopefully it will not be worse than the TSW1 counterpart as all reserved collection