You do not need to narrate every day
A travel journal can be visual, tactile and fragmentary. A ticket plus one sentence can hold as much memory as a page-long diary entry if that is the way you naturally remember things.
Collect first, interpret later
During the trip, simply notice and keep. You can punch, arrange and paste in the evening, on the train home or even after the trip. The collecting itself is already part of the experience.
Use prompts instead of blank pages
Specific prompts reduce the pressure of a blank page. Find something blue. Keep a word you learned. Save a tiny map detail. Choose the thing that made you smile. Small missions are easier to begin than 'write about today'.
Leave space unfinished
An incomplete journal is still a record of the trip. The empty spaces are not failures. They simply show what you noticed — and what you did not.