Spain's LZB rail system: safe but obsolete, drivers and controllers say

Spain's train drivers and traffic controllers agree on one point about the LZB signalling system on the Madrid-Seville high-speed line: it is safe, but obsolete. Transmission failures, they say, are routine.

The line is due to swap LZB for the more modern ERTMS-2. Drivers consulted say the new system is not safer in itself, but it is newer, and that brings advantages. LZB relies on a cable laid along the track to mark a train's position, its speed and the space available up to the next train.

The drivers' union Semaf considers the Urda accident unusual, because a fault of that magnitude is not common. What is common, it says, are transmission failures, "like when a computer crashes and restarts, then works again". Anonymous drivers confirm this and link it to some delays. Semaf argues the system "is obsolete, should have been replaced a year ago and perhaps is not being maintained as it should".

Degraded running and theft

Every transmission failure means more running in degraded mode, when LZB drops out and the driver relies on lateral signals and instructions from the control centre. Semaf says this raises risk without making LZB unsafe: using one anchor instead of two to paint a facade, as it puts it, is simply a matter of probability.

Raquel Ayllón, a controller and spokesperson for the SCF union, says the cable is stolen for its copper, and the more anomalies occur, the more is taken. She says ERTMS works with balises and fails less, while ERTMS-3 could run trains autonomously but has not been bought as in France and Germany because it is more expensive.

Maintenance and staffing

European Commission data cited in the debate show Spain spent almost 1.5 billion euros on railways in 2018-2022, with 16% going to track maintenance against 30% in France and Germany. In 2022 Spain spent 95,860 euros per kilometre of high-speed line maintained, versus a European average of 191,090.

Ayllón also describes staffing shortages at the Atocha control centre and says maintenance work once done by Adif staff now goes to subcontractors with poor training. The investment deficit is put at up to 3.6 billion euros. Unions say they warned of these problems before and after a 2026 marked by two serious rail accidents.