Allo wallon.

You can take as many trains as possible/feasible on a chosen day-and use them till final end even if its past 0.00. It is NOT 24 hrs-its a calender day.

Main obstacle will be to get the needed REServations for seat on €* and in that Cale. Caled has NO couchette, it has only recline seats (like airplane) and real sleepers and I understand as single you need to call them and reserve whole comprt for you (its 2 beds inside). This will cost a lot. @2-I guess these are (about) right-Caled is in GBP so may change a little in € as exchange rate

@3-its all on the site-just search. You can even set it to this FRench lingo.

Here is information about the Caledonian Sleeper.

https://www.interrail.eu/en/plan-your-trip/trains-europe/night-trains/caledonian-sleeper

I believe this page is outdated. Supplements have gone up since the new trains arrived and you can now only book complete compartments as far as I know.

Booking instructions for the Caledonian Sleeper are here. Also check normal fares because they can be lower than the Interrail reservation.

Eurostar can be booked via (among others):

• Interrail website (booking fee 2€ per person and train)
• Belgian railways ticket office (the ones that do international reservations, no booking fee).
• Belgian railways by phone (no booking fee but phone costs).
• French railways by phone (should be cheaper to call than the premium Belgian number)
• Belgian railways website (booking fee 4€ per order).

Thanks @rvdborgt for being observant. If the page on The Caledonian Sleeper on Interrail.eu is outdated then the info should be updated. Do you have someone to inform about that?

That used to be @Nanja but I'm not sure she's back in the office yet.

Just to confirm: the information has been adjusted as far as I can see, a few months back.