Alaske - Rail vs Motorcoach - ideas?

[Gidget22]

We are thinking about an Alaska Cruise on Princess. The Cruise tour says "Motorcoach may be substituted for rail on some departures". Does anyone know what that means? I was hoping to get the rail on the way up and back to the lodge and wanted to know what the chances that we would not get that as booked.

[Budget Queen]

I don't see any reports of this substitution. I would think it's going to be a rare event.

[Gidget22]

thanks!