From ticket punchers to magnetic strips: a revolution for the Paris metro

With Maxime Donal,
Former Head of SESA’s Telecommunications Division
And Jacques Arnould,
Former technical director of SESA

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From ticket punchers to magnetic strips: a revolution for the Paris metro

“Tickets please!” There was a time when each Paris subway ticket was inspected and validated by a ticket puncher. How did we go from that to automated turnstiles? With a little help from Capgemini, of course!

The age of ticket punchers

In the mid-1960s, Paris metro tickets were checked by special agents known as poinçonneurs, or ticket punchers, like the one featured in Serge Gainsbourg’s hit song, Le Poinçonneur des Lilas. Armed with a small hole-puncher, he punches tickets one by one as passengers enter the metro. At rush hour, the subway platform is packed…

500 million
Passengers who used RATP transportation in 1970.

In 1966, the public transport agency in Paris, RATP, decided to automate its proof of payment process. “Traffic continued to grow and ticket punchers were finding it increasingly difficult to validate all the tickets. The introduction of computers became indispensible to streamline passenger flow and improve our service,” says Jacques Arnould, then CEO of SESA, acquired by the Capgemini group in 1987. The idea was to give each rider a ticket with a magnetic strip and replace ticket punchers with turnstiles capable of reading the ticket information.

This type of project required more than engineering skills. It also took creativity and imagination to overcome the difficulties involved.” Maxime Donal

SESA was tasked with designing and implementing the ticket validation software, and was given full control of the IT side of the operation. The company enjoyed a strong reputation in terms of automation, its CEO, prior to SESA foundation, having already built France’s entire air defense system, from identifying threats to launching fighter planes.

October 1973
When the last poinçonneur punched his final ticket.

Tons of data in a few milliseconds

The major challenge was the data processing speed: “The period between the turnstile reading the ticket and the gate opening had to be extremely short. Without this, the system would cause traffic jams or even accidents during rush hour,” explains Arnould.

SESA designed a solution that would avoid this pitfall. “Artificial intelligence was employed both in the ticket readers at each station and on the central computer that processed all the information contained on the magnetic strip,” he continues. “Information on the strip was sent to the computer for processing. Next, the data was transmitted to the turnstile where it was recorded. Then the data was sent back to the central computer, which granted the authorization to open the gate. Finally, the data returned one last time to let the passenger pass through… and alI within 200 milliseconds for thousands of turnstile!” depicts Maxime Donal, then Head of SESA’s Telecommunications Division— simply remarkable.

It was essential that the information processing times go unnoticed. There could not be any wait time at the turnstiles, particularly during rush hour. It was an immense technical challenge that we successfully overcame.” Jacques Arnould

A world first that got everyone talking

Rolled out between 1969 and 1973, the automation of the Paris metro was a world first, not only due to the data transfer speeds, but also because of certain techniques used. “Since there was no way to wire all of the turnstiles to the central computer, we invented a brand new connection that would later become ADSL,” concludes Jacques Arnould. SESA’s groundbreaking system quickly conquered the rest of the world. During the 1970s, it was adopted by subway systems in Rio (Brazil), Montreal (Canada), Seoul (South Korea), Hong Kong, Baltimore (United States), Caracas (Venezuela)...

200 milliseconds
The data processing time between the turnstile and the central computer.
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