- I'm sure this station is ...
absolutely, it's large. you'll see many large stations in London though. London is overwhelming in stations and tunnels but everything is really well-documented, so you'll have some practice.
If the station will be busy (this will be a Saturday in July)
always, plan for it to be full. but also be aware that people will give space and you'll be fine for that reason. easier than London, since London as a whole is simply too busy a machine to accomodate someone walking a different pace. Brussels has many influences and you'll be able to cross the station in peace.
I am travelling with a friend and
we will both have suitcases with us
don't worry about luggage, the stairs are in good shape and the floors also. the station build is pretty much like an airport, but made of flat stone. you can - if you wish so - run through the hallways with your suitcase behind you and could even fly down the stairs without much risk (but please don't). Only take to elevators if they are already at your level and there's no queue larger than what goes through the door. you can lose insane amount of time just to get on an a piss-stenched elevator. In London that might work but in Brussels you definitely will also just have a lot of people too stupid to get the door to close etc.
You might have to lift it up onto the train though. They have a lot of double-decker trains with steps to enter them and they generally don't have elevated platforms.
If a platform change is normally this short
yes, for a large station like that 5 minutes is tight but still doable. Knowing the station but not the platforms, I'd say you need 10 minutes for safe changeover and have 3 minutes spare. For myself I have like 8 minutes as OK and anything under is a bit in the red.
what I'd like to pass on since it wasn't said. Maybe I'm just the negative guy but I found Brussels a special case calling for a different attitude:
I travel a lot, but found announcements in Brussels are generally confusing. It would be highly helpful once you're on your platform to try find someone you can ask "is this my train?". Sometimes I've had it that suburban train goes to my long-haul station and drops off people and then goes on, all while mine is on the display for later. Or mine arrives 20 mins before depature - and threre's no annoucement, some people enter, the tourist still stand outside confused. There's also no guarantee that there will be an announcement in english before departure just because there was one 10 minutes ago. (grrrr)
so really, try to check with people on the platform. a lot only speak french but usually there's someone.
Another thing to know is: there are MANY connections from Brussels, sometimes 3 to the same place within a few minutes.
So be sure to be able to identify your train by the final and next destinations. Some even have non-national destinations you'll not be able to just guess.
Check online which platform it's gonna depart from, check a station map to know where you'll arrive and where the other platform is. check the platform on every screen that lists your train and especially before you go down to the platform. There's usually a display on the hub floor right next to the staircase.
After going through Midi and Centraal around 20 times without speaking the language and usually in a rush, at times doing the 30 minute run to the Chocolatiers district and picking up chocolate between trains, getting lost between the many side entrances to the platforms, my real advice is: In Brussels, just be resilient and if it happens, let it happen.