A Train with a Flight Number: Brussels Airport to Cologne
From 7 September 2026, Brussels Airport gets a direct high-speed train to Cologne, and the rail leg carries a Brussels Airlines flight number. Deutsche Bahn and the airline are running it as a codeshare, which changes what happens when the train is late.
The service
Two return services a day between Köln Hauptbahnhof and Brussels Airport, calling at Aachen, Liège and Leuven, then continuing to Antwerp. Journey time from Cologne to the airport is around two hours, covering roughly 200 kilometres. Tickets are already on sale through airline sites, travel agents and rail booking channels.
Why the flight number matters
Plenty of airports have a train. Very few have a train the airline treats as one of its own flights.
Under the codeshare the rail segment is ticketed with a Brussels Airlines flight number and the onward connection is protected. A delayed train that causes a missed flight becomes the airline's problem to solve. Book the train and the flight separately and that risk is yours: miss the check-in cutoff and you have bought a new ticket.
The protection attaches to the through booking, not to the route. Buying the same train separately because a rail site quoted less removes the only thing that distinguishes this service.
The model has a track record
This arrangement is not an experiment. Lufthansa and Deutsche Bahn have run Lufthansa Express Rail for more than twenty years, feeding Frankfurt Airport by train from 28 German cities. More than 240 ICE connections a day carry a Lufthansa flight number, and arriving or departing passengers can connect to up to 24 stations as part of a single flight itinerary.
The German version has kept adding to what the ticket covers. Since 2025 a Lufthansa Express Rail boarding pass is also valid on local buses, trams, underground and suburban trains to and from the rail station at either end, which removes the last unbooked leg of the journey. Air Canada extended its own codeshare onto the rail services in June 2025, so the flight number on the train can belong to an airline that does not fly the route at all.
What all versions share is the transfer guarantee: when the train fails, the airline handles rebooking rather than treating you as a no-show. That is the substance behind the Brussels arrangement, and the reason it is worth more than the two hours it saves.
What it replaces
Cologne Bonn Airport is close but thin on long-haul routes, so passengers from the Rhineland have been driving to Brussels or riding the existing ICE to Brussels-Midi and changing there.
That final leg is short but fiddly: 12 kilometres, 22 to 24 minutes, trains roughly every ten minutes, and a change with luggage in a large terminus. Around 110 trains a day run it.
One charge catches people regardless of route. Journeys to and from Brussels Airport carry a rail surcharge, the Brussels Airport Supplement formerly called the Diabolo fee, currently €6.90. It is normally built into the quoted fare rather than collected at the barrier.
The limits
Two services a day in each direction is a thin timetable. It fits a morning long-haul departure and an evening return and little else. Outside those windows the Brussels-Midi route with a change is still the answer.
Allow more arrival buffer than the journey time suggests. Brussels Airport is a Schengen external border for long-haul departures, and border processing across the area has been markedly slower since the EU's new entry and exit checks reached full operation on 10 April 2026. Ninety minutes between arriving at the station and a long-haul departure is tighter this year than the same plan was two years ago.
What the stops along the way are worth
Aachen sits about 70 kilometres from Cologne and has no airport of its own worth the name, so its long-haul options have always meant a transfer to Düsseldorf, Cologne Bonn or Brussels. A direct call on this service turns Brussels into the practical hub for the city.
Liège gains the same way from the Belgian side, and the continuation to Antwerp gives northern Belgium a second through route to the airport that does not pass through Brussels-Midi.
Leuven benefits least. It already sits close to the airport on the existing network, so the through service removes a change rather than a journey.
When the road still wins
Groups of four or more, departures outside the two daily slots, and anyone starting somewhere the line does not serve. Four rail fares plus a missed-connection risk compares differently against one fixed price for a car, and a car does not care what time the flight lands.
The same applies to the awkward hours. A long-haul arrival at 23:00 in Brussels with an onward journey into the Rhineland is not a train problem any timetable solves this year.
For one or two people travelling between Cologne, Aachen or Liège and a long-haul departure from Brussels, the through ticket is now the straightforward choice.
