This month a new train service has been launched between Brussels and Vienna. This is an opportunity that I have been waiting for a while, and I really hope they do not cancel it before I have a chance to take it.
Weekly train frequencies along the route:
UPDATE (17.02.2020): As a result of the successful launch and high demand for the train service, the frequency of the train will be increased at least to three times a week from December 2020.