Hacker News Reader

Comment by djhworld | Hacker News Reader

I lived in London for about 10 years and used the Oyster almost exclusively (with auto-topup enabled)

The biggest advantage I found was the latency between you tapping the card on the reader and the acknowledgement "beep" to let you through. Always seemed extremely responsive to the point where you get used to the motion of going through the barriers with one fell swoop.

When using anything else (e.g. credit cards/Apple Pay/whatever) the difference always seemed jarring, like maybe an extra 200ms-300ms longer for the thing to light green.

It might have gotten better since I was there though.

View on HN

I use the “Express Travel Card” feature with Apple Pay now and it’s as fast as oyster was (in the wallet settings). I walk up to the gate with my phone in hand, locked, hold it over the reader and it’s super fast. I remember the slightly delay in the early days (plus verifying your ID with touch/face in advance of the gate) but I think it’s a solved issue now.

Yes! The Apple express speed is phenomenal, it beats anything else I’ve tried. Sometimes I feel like I’ve barely taped my phone and I’m gone.

I can't find a source, but I recall reading that the staff oyster cards were significantly faster than the oyster cards provided to the public (~100ms rings a bell).

I'd love to read it again if anyone has this information

No need to check for topups/updating a db potentially?

In that context they are likely more of access badge than payment system. Thus far fewer steps to communicate and possibly even local copy of access database.

I have heard something like this from colleagues, and I can confirm that staff Oyster cards are very fast. But I've always felt that regular Oyster cards are very fast too, so I don't notice much difference.

When the validator detects a staff Oyster card, it does check if the card is hotlisted (in case it was lost/stolen). But otherwise there's very little logic required.

The old Oyster cards were really fast. But they had a security flaw, so they had to be replaced with newer ones that are slower to use :-( Both are still faster than a credit card.

Do you know why Oyster cards are so seamless?

Presto in Canada is built on similar technology, but no existing implementations were used because it's more expensive that way (thanks capitalism!)

For us, the tap takes half a second. If a queue forms, you'll be waiting awhile. It takes 2-3s if your card is in a purse, too.

Purse notwithstanding, it probably takes that long because the balance is not stored on the card. A round-trip to an external server is required.

Worse yet, if you try to use a freshly loaded Presto card on a terminal that is not internet-enabled (read: city buses), you cannot, because the offline terminal is only synced once a day. Don't even get me started...

IIRC Japan's FeliCa (Suica, PASMO, etc.) is much faster because it had more stringent timing requirements in the spec because of how many people they needed to be able to walk through a turnstile, which increases the cost of the associated hardware (the readers in the turnstiles/trains/buses, as well as in e.g. iPhone chips).

IIRC Presto does store the value on the card -- when you load value online, every bus/train/turnstile gets a batch data file of cards it needs to update the balance for, and checks every card that passes through it to see if yours is one of them, and then writes the updated balance to the card. But the slower scans are due to the choice of a different standardized transit pass format (one that allows for much slower -- IIRC, hundreds of ms -- reads/writes than the Japanese standard).

Thanks for the explanation! I didn't know Presto stored that kind of data on the card and assumed otherwise given the lag time.

I stand corrected!

For the Japanese cards, there are Android apps that can read the last several transactions using the phone's NFC chip, so there's obviously local storage there too. Although my guess is there's redundancy with online data to ensure there's no shenanigans.

The cards also work on other things, like the many vending machines in Japan, I wonder if they're all online. Maybe the protocol is designed that subtractions are easy but additions are hard...

The Presto app also does that, and you can top-up the card by tapping your phone's NFC reader as well.

This is incorrect.

The balance is stored on the card, in fact the balance being stored on the card is something that people complain about constantly because there is a 24 hour period where the buses need to return to the depot to update and people hate that.

Reply on news.ycombinator.com