A first-class single ticket from Stockholm to Berlin in the 1900 cost SEK 86.20. A return ticket cost SEK 112.90, but the return ticket had to be used within 30 days.
We know that the von Hallwyl couple took express train No. 1 from Stockholm Central Station on 5 November at 7pm. The train went to Trelleborg. From there they took the ferry to Sassnitz and then another train to Berlin. According to the timetable they arrived in Berlin at 8:43pm on 6 November. We do not know how much the tickets for the remainder of the journey cost.
The tickets in the picture are examples of train tickets of that period. They can be found in the Hallwyl Museum archives.