Because they have no idea that there are two separate concourses. They get off their train, go up the stairs/escalator to the concourse and find a glass screen preventing them reaching the platform they need for their next train.
This thread (at least in relation to Birmingham New Street) is perhaps suffering from lack of shared understanding about what certain words are intended to mean. I have tried to approach the discussion from the perspective that there is only one 'concourse' - essentially the non-paid/ticketed area that you can walk into from Stephenson Place, The Bull Ring, Hill Street, taxi rank and so forth. I think that you are actually describing the Blue and Green Lounge, which are 'railside'/paid area, albeit at 'concourse'
level.
But have no fear! It rarely takes more than a minute to cross from one lounge to the other via two barriers, which is no different from what would be necessary at many other transport interchanges. As other posters have confirmed, pretty much every valid 'ticket'/barcode is usually accepted.
As a tip, anyone who goes up 'stairs' (other than from Platform 1B) is not taking the 'safest' route for interchange. The 'B' bridge/Red Lounge is basically reached by escalators. (I accept that there are lifts at both ends, so the distinction is less obvious if you are using those, and there are escalators at the 'A' end too.) But
stairs! Definitely a bad sign.
https://www.nationalrail.co.uk/stat...-made-easy/birmingham-new-street-station-plan suggests the above is wrong about barriers and my memory is correct. There barriers are shared: one set for 1A-5A, another for 6A-12A and another for all the Bs and 4C.
Illogical and inconsistent is a good summary of the New Street station design! Any time your designer wants to give the concourse coloured zones (instead of the platforms) send them back to the drawing board.
My point was that to access any and all platforms at New Street you have to pass a barrier. I.e. it isn't like some other stations, such as Euston or Glasgow Central, that have barriers for some platforms but not others.
Yes, obviously for a two-level, non-terminal station barriers end up being 'shared'. There are actually
two sets for 1A-5A (Blue Lounge),
two sets for 6A-12A (Green Lounge) [These can also be used for the respective B sections of those groups too if you want! Just talk along the platform.] There are also two sets giving access to the B bridge/Red Lounge
and these can be used to give access to any part of any platform, not just the Bs and 4C!
And, fortunately, the barriers at New Street aren't often in operation. The concept that I have to use my ticket to change platforms is completely unacceptable to me, I loathe it. As a result, I avoid them and any opportunity for retailers to take money from me, which is presumably contrary to the objective of the redesign.
I am sorry to hear this. I hope that in your journeys from Wilmslow you never have to try changing at Liverpool South Parkway, Liverpool Lime Street, Glasgow Central, Edinburgh Waverley, onto the Underground with a cross-London ticket at Euston and so on.
Fortunately you never have to use the barriers at New Street if you are just changing trains! Just remember to use the B bridge/Red Lounge (and I can assure you that it isn't compulsory to buy a coffee).
I presume that you never walk past (let alone patronise) any shop, cafe, pub or other retail establishment in the wider world?
Adding to zotGD's comments, a good design is intuitive. If people follow every sign, and listen to announcements, chances are they'll get around New Street OK. But I can get around most airport terminals, for example, without needing to do that - just by following what looks like the right flow, chances are you get where you need to go.
Ah! I think that we may be onto something here.
This thread is obviously about 'Interchange Stations'. Whilst New Street is certainly a key interchange it is important to realise that the substantial majority of its users alighting from a train are likely to be exiting the station rather than switching to another platform. Quite probably the regulars will be making a point of deliberately
not using the B bridge/Red Lounge in the interests of leaving the station quickly and in a slightly less crowded environment. So if you are 'following the flow', you are likely to end up in the Blue or Green Lounges!
Obviously your tactic can work in some places. Alighting at Wembley en route to the stadium you are probably OK following several hundred other folk wearing similar fan gear or else at Weston-super-Mare following masses of bucket and spade toting families to the beach. But a bad idea in Brum.
As a final thought, I was on a CrossCountry train earlier this week through New Street. The Train Manager had helpfully given the usual arrival remarks about connections and the B bridge. An American at the next table was engrossed in watching a film on a laptop whilst wearing headphones and clearly heard none of this helpful advice. We pulled up in the platform and my fellow passenger came to his senses with a start. "Hey, Bud, is this Birmingham New Street?" I confirmed that it was. He snapped his laptop shut, scooped it into his bag and ran for the door...
This had all the potential to end badly but none of it was due to either front line rail staff or the architects of the station.