How we check prices

Every price on Tramfox comes from the transport operator’s own fare page and carries the date it was last checked against it. This is how that check works, and what it cannot do.

Where a price comes from

Each city’s fares are read from its operator’s own pages, and every city links to the operator’s price page. For one city, Palma, a small program reads them from the operator’s ticket system. Nowhere else do operators publish their fares in a form a program can read, and most of their pages turn away plain downloads, so the pages are read in a web browser.

Who reads them

An AI agent does the reading: it opens the operator’s page in a browser. Tested code, not the agent, then compares every amount on the page with the prices on file and lists what is missing and what is new. Each difference is read in context on the page before anything changes, because an amount on its own does not say which ticket it belongs to.

What catches a mistake

Before a change is kept, the same checks that guard an automatic import run over it. They flag a price that moves by 15% or more, a ticket that disappears, and any change to who may use a ticket or how many people it covers. They also price a set of typical trips before and after, so a misplaced decimal shows up as a trip that suddenly costs a tenth of what it did. Then a person reads the complete change before it is published. Nothing reaches this site without that review.

The dates

Each city says when its prices were last checked and, where it differs, when they last changed. A check that finds nothing new still moves the first date, and only a check does: it is never moved because a file was edited, or to make a city look fresher. If a city goes more than 400 days without a check, our own build fails until someone checks it.

What checking has found

Checking is not a formality. When our early prices were first checked against the operators, three cities had real errors. London’s single fare was 16% too high. Berlin and London were each missing a monthly ticket, which made a 30-day trip three times too expensive in Berlin and 15% too expensive in London. Paris still carried a discount the operator had withdrawn, so a single came out 18% too cheap. All of them were corrected.

What it cannot do

A price is right on the day it was checked. Operators change their fares, sometimes without notice, and this site can be wrong until the next check. Reduced fares are left out unless you ask for them. Some cities are described rather than priced, because their fares depend on something a trip form cannot ask, such as the zones a journey crosses or the distance travelled. The operator’s own page is the only binding source.

Who makes Tramfox

Tramfox is a non-commercial project made in Vienna. It sells nothing, takes no commission and carries no advertising. Found a price that is wrong? The address in the legal notice reaches us. Legal notice