I’m planning a trip to Mannheim in Germany and hoping to bring my bike along. That’s meant having to make sure I can bring the bike on the trains I’m mostly using for transport (there’ll be some ferries too). The bike I’m bringing is the Hercules Bikes Rob Fold R7

From the ground to the highest part of the handlebar is 108cm, the width in this photo is 82cm and the depth is approximately 20cm. So it’s still quite substantial when folded!

photo of the Rob Fold R7 bike folded

Eurostar

For the trip I'll be travelling by Eurostar for:
  • Paris to Amsterdam
  • Brussels to London

I thought things would be a bit more liberal in relation to bikes on the Eurostar but it’s complex enough and there are additional booking fees. If you have a look at the “Bikes on board” page there are two tabs

Travelling to and from London

Here they say they’ll treat a folding bike as luggage if it’s no longer than 85cm in length

Travelling between Belgium, France, the Netherlands, and Germany

Here however they say

We treat folding bicycles as standard luggage items as long as the maximum dimensions when folded do not exceed 75 x 53 x 30 cm.
which my bike will exceed.