No. The O-Train uses a different station in a separate building adjacent to the Ottawa Station. The land the O-Train is using is mostly owned by the NCC (though they are using a corner of VIA Rail's land) and the land Ottawa station is on is owned by VIA Rail.
I'm not sure why you point this out, but the name of transit stations usually reflects what they are built next to rather than who owns the land they are built on...
I noticed that, but government agencies are not immune from making mistakes.
That is of course uncontested...
Thanks for sharing the picture!

There is certainly no debate that at one time it was
a union station (lowercase u and s), but the debate is if it was ever given
the official name "Union Station."
...and following some debate which our little dispute has sparked on groups.io, I have to concede that even though "Union Station" seems to have been the intended name for the new rail station built on Tremblay Road, the name was changed to "Ottawa Station" before it was opened. The full debate can be accessed directly on
groups.io, but I'm just quoting the two older posts with which Tom Box introduced the debate:
Furthermore, Tom Box points out that this change in name seems to have been causing confusion from the day of opening and I'm kind of reluctant to hold the editors of the "European Rail Timetable" to higher standards than "The Globe and Mail":
[...]
A brief story on p. 35 of the July 30, 1966 Globe and Mail says, "The capital's new Union Station, two miles from downtown, will open tomorrow with the CPR's North Shore dayliner to Montreal scheduled to be the first train out at 9:05 a.m." So there was confusion over the name from the outset.
https://groups.io/g/Canadian-Passenger-Rail/message/90359
According to that map, VIA owns the building on Terminal Street that backs onto the station. Good on them for having the foresight to acquire it, since it keeps the door open for an entrance on the south side of the tracks.
AFAIK, it was always theirs and is some type of service building (it has the same, "
award wining,"
blank concrete wall architecture). I believe it is connected to the station via a tunnel. If you look back at old areal photographs of the station, you will see that it used to have tracks filling in the space between the buildings, but at some point the land was sold and the tracks were torn up.
I'm almost certain that
@roger1818 is correct and that the passenger tunnel connects to that building. However, opening that tunnel as a pedestrian thoroughfare would cause severe crowding and crowd control issues and could consequently be highly problematic...
Exactly. In Ottawa it is especially difficult as all station names need to be bilingual.
Yes, that's much more trickier than I thought, now that we know that "Union" doesn't work in French...
I don't disagree that calling the O-Train station Tremblay is problematic and should be revisited. I do understand why they didn't want to call it train though (calling a train station "Train" is strange). I don't think it is as big a problem as
Urban Sky is making it out to be though. When you arrive, all you need to know is you need to find the "O-Train" station and that can be solved with appropriate wayfinding inside VIA's station. That is no different to knowing that you need to find an "S-Bahn" station when you fly into many German cities. When it is time to leave, you have then become more familiar with the city and its transit system, so while needing to know that the statin you need to go to is called Tremblay is not optimal, it isn't that hard to figure out (they likely came from that station when they arrived).
Visitors don't necessarily leave a city the same way they arrived in it: during my first two visits to Canada, I landed at Ottawa Airport and I started my first ever trip with VIA Rail at Ottawa Station (note the correct use of name!

). Also tourists are quite likely to just jump into the first taxi they see after arriving in a new city (thus paying little attention to where the terminal of their arrival is located), leaving the task of figuring out the city's transit network for after they've checked in at their hotel and stored their luggage.
And as for your example with German cities, this is how they name the rail transit stations of their largest hubs (provided for the 11 largest airports I found listed
here):
I think we can all note a pattern here (and you now know what "Airport" and "Central Rail Station" are called in Geman - and how the latter is commonly abbreviated)...