Edit: wait, I know one in Germany as well. It's expensive but between Frankfurt airport and another major city, there is a rail line but somehow the bus is significantly faster and they're using double deckers. The front row at the top was, n=3, always free for me (all four seats) so you get a quite unique experience, at least so far as my bus experiences in mainland western Europe go :)
Often true. OTOH, the reduced footprint (vs. either 1 articulated or 2 normal busses) can speeds things up, especially on cramped and congested city streets. And if you're getting near gridlock-level congestion, the length of the articulated busses can be like dumping gravel into your system's gearbox.
cant they just put another entry door?
My local transit agency just stopped allowing rear door boarding, and that was one of the main reasons: https://waypointblog.com/capmetro-is-ending-rear-door-boardi...
People want to get to work on time after all. Entering and leaving the tram or bus through all door is a simple way to improve public transports reliability.
Double-deckers are cool, I’ll grant you that. And a very nice way to visit a city. But they are far, far less efficient in terms of capacity.
> need a large harmonica to deal
I'd guess you mean "large accordion". Either way, the size & complexity of that joint section may be why the idea never went anywhere.