Such a system has been in use in Singapore for more than 15 years.
Vienna does away with all of this fuss by simply doing random checks, issuing on the spot fines for fare evaders, and not having to manage the expense of turnstiles etc.
Vienna does away with all of this fuss by simply doing random checks, issuing on the spot fines for fare evaders, and not having to manage the expense of turnstiles etc.
I kind of like the barriers, if you are on the station platform, then you have definitely paid. For me, the stations that don't have barriers are more stressful, as you run the risk of forgetting to tap your card (or the tap not registering) and incurring a maximum fare.
Tag in and forget to tag out, you pay the maximum fare.
Forget to tag in, hope you don't get checked. There is no option to tag out without having tagged in. (Although I've seen this happen to someone, and he was just given a warning.)
Get checked without having tagged in, pay $400, which is about 30 times the maximum fare.
I definitely prefer the proof-of-payment setup more. London (which has turnstiles) can get crazy backups with people trying to tap into / out of the system, and the Berlin system lets you engineer more convenient and therefore customer-friendly stations -- no need for mezzanines, paid vs free elevators, and the like.
And promptly got pulled off the train at the next stop for not paying.
They were very understanding when I explained I had only been in the country about two hours (and showed my passport stamp as proof). They explained that there are machines to punch holes in the tickets... I did think it was strange that there weren't any turnstiles, but I figured, maybe you run into them on the way out or something (and I had only been in a foreign country two hours, everything was strange).
It's pretty common for smaller stations near major football stadia to have the barriers controlled manually after big games -- totally open for some minutes, then completely shut until the platform has cleared.
(London used to have a proof-of-payment system on the articulated buses, since you were allowed to board at any door, and it still exists on the trams.)
Local bus drivers will sell tickets, but there are also ticket validation machines in the middle of most busses. Local trains and subways are trust basis, but I've seen more random ticket checks recently. Ticket checks are more frequent on long-distance trains, but still, no barriers. I have yet to travel on local or long-distance trains in Germany or Austria that aren't trust-based.