Wien / Vienna to Bruxelles / Brussels by train

Booking places in the sleeping cabins

When entering 2 travellers as 1 male and 1 female, you will automatically be given the option to book a 3-bed cabin for the sole use of the two of you - the 'double' cabin option.
So you will be in the cabin together with no other travellers.

3 men + 2 women or 3 women + 2 men = three beds in a triple cabin + two beds in a double cabin is what you will be offered, though the cabins will then be male and female only.
So if the combination of travellers is 1 male/female couple + 1 male/female couple and a child, you will need to make two separate bookings so that the two couples can each share a cabin.

When 4 Adults are travelling together you will be given the option of booking double or triple cabins.
If you select 'Double' you will automatically be assigned 4 beds in two double cabins.
Because the Triple cabins are segregated into male and female, when two women + two men are in the travel party, the two men will be sharing a triple compartment with another traveller, as will the two women
When 3 men + 1 woman or 3 women + 1 man are the travel party, the fourth person will then be sharing a three bed cabin with two other people.

OBB is the national rail operator and its booking service offers journeys by express trains within Austria, as well as international journeys which don't involve making a connection outside of Austria.

It pays off to book online, as the discounted 'Sparscheine' tickets are only ever made available on the website, and when making international journeys to and from Austria, these Sparscheine tickets tend to be cheaper.
OBB can offer particularly good value for money when travelling with children on international rail journeys, but something to watch out for when travelling between Austria and Germany on daytime trains, is that reservations are an optional extra; but if you book 1st class tickets with the Germany railways website DB, the reservations are complimentary.

OBB often takes a unique approach to its booking path, but a key thing to keep in mind is that the first price you will see for any journey is that of a Second Class seat.
The costs of upgrading to first class, a reservation, or a sleeping cabin etc, is then added to this price.

DB is the national railway operator in Germany, so its website can be used for booking journeys by German express trains; the ICE and IC trains and it doesn't charge booking fees.
It also sells tickets for journeys by direct trains on all international routes from Germany regardless of whether DB is operating the train service.

It also sells an extensive range of end-to-end journeys which involve making connections both within Germany and in neighboring countries, but journeys between Germany and Britain cannot be booked on DB.

A key feature of DB website worth keeping mind is that it offers 1st class ticket purchasers complimentary seat reservations on journeys both within and to/from Germany.

Seat reservations for daytime in both 1st and 2nd class can also be booked separately from tickets.