“The train record of safety in Europe is constantly improving,” said Jens Engelmann, head of the directorate for the European Railway Agency, which monitors and sets train safety standards. “The systems that are in place are working well. There is no link between the accidents as far as we can say for the moment.”

Others are less convinced, and there is growing public pressure to install the latest automatic braking technology, as well as calls to reverse some staff cuts that have left drivers alone in the cab and complaining of longer hours that can lead to human error.

“There used to be a station agent and someone on the track and the driver,” said Giorgio Tuti, the president of the Swiss transportation union SEV. “Now there is only the driver on the train, and no one accompanies him. It’s been an evolution that started in the 1990s when they eliminated track employees.”

He added: “It’s too much risk to let all the monitoring be done by the train driver, and accidents will happen. It’s almost the same in Spain. You have a high-speed train, but they were still using an old system.”

Many national lines rely on outmoded systems that date back to a time when there was less traffic, as in the case of the speeding train in northern Spain.

Leaked documents from the crash investigation, published last week by El País, a Spanish newspaper, indicate that an alert went off twice before the derailment but that the train’s unsophisticated automatic braking system could only partly slow the train.

That is where the European Union’s transnational signaling technology — the European Train Control System — is supposed to play a critical role. The concept of that system is basic: information is electronically transmitted from the track to the train to an onboard computer that calculates the maximum permitted speed and that can automatically slow a train.