It's a good idea to carry a couple cards.

About a decade ago, I took a sudden flight to a small airport in Colorado due to an emergency at work. When I arrived, I had nothing but a Visa, and a few dollars Canadian.

I was frustrated to find that I couldn't get food or call my work, because Visa wasn't accepted anywhere. The highlight was trying to make a call on a payphone and talking to the operator. When I asked if I could use my credit card to make a call, she listed off MasterCard and a half-dozen credit cards I'd never heard of. "How about Visa?" "No, sorry."

I will forever remember the janitor for lending me his cell phone and getting me out of that mess. After that, I made sure I carried multiple cards.

This. I ride not-particularly-reliable motorcycles. My personal philosophy is to always have access via at least two different financial institutions and their computer networks to sufficient debit/credit funds to get myself and a possibly broken bike home from the most remote place I could possibly end up on a trip.

(I did once end up having a tremendously fun weekend in Melbourne thanks to a broken down bike and a weekend long outage of my then only bank's ATM network - but it would have been even more fun with more than the cash in my pocket and relying on friends for somewhere to sleep until a branch opened on Monday morning...)

On the London transport network you've been able to pay at the barriers with a contactless credit card in the same way as you would use an Oyster card for a couple of years now. It's weird that other transport networks haven't adopted it yet

It's being trialed in Sydney http://www.smh.com.au/nsw/the-new-opal-commuters-to-trial-sw...

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.

Neither the ez-link or NETS FlashPay cards are credit cards. The SG trial of contactless credit cards for public transport micropayments kicked off only last month. http://www.straitstimes.com/singapore/transport/tap-masterca...

How do you pay for tickets in Vienna then?

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.

In Nürnberg, you can either buy paper tickets from ubiquitous automats or in the local transit app (with a pre-configured credit card or current account). I love it.

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.

Berlin has a similar proof-of-payment system, where there are no physical barriers between the street and train platforms. Most people have multi use tickets; you can buy week, month, or year long tickets.

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.

That's what caused me to get stopped by the police my first day in Berlin a few years ago. I wanted to go to a board game store, so I looked one up on Google in the hotel lobby, walked to a u-bahn station, paid a couple euros for a ticket, walked downstairs and got on a train.

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).

FWIW the police does not perform ticket checks in Berlin. Traditionally it was done by employees of the public transport company and now increasingly by third party contractors.

It might have been some security guard thing, I don't remember. It was a few years ago.

Some stations in London can be so busy, that they'd need some way to prevent people from overcrowding the platform even if there were no barriers.

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.)

Maximum fare?? The fine for fare evasion should be well above the maximum fare.

In London, the barriers automatically charge the maximum fare if you forget to touch in or out of the system. It helps because you can jump the barrier to get into the system but you never know if ticket inspectors/security will be present at the station where you plan on alighting. The penalty for being caught jumping the barrier is significantly higher.

Caltrain (the heavily dysfunctional system serving a minor portion of the San Francisco Bay Area) is similar, but a little less convenient --

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.

Or, looking at it from a different perspective, the fine is maximum fare by definition. Then you can pay the posted fare or decide whether the expected fare based on fine x probability of capture

Fine on Nürnberg's system is 60 EUR - plus maximum fare.

That's how it works in Chicago.

If you use your main card at a major retail store it has just as much chance of being involved in a hacking incident as the online card.