The railway workers ask the Security Agency to extend the mandatory double human control to all critical processes that depend on a single person

When the automatic blocking systems that keep trains separated fail, a single person can undertake the necessary checks to determine whether a section of track is free and authorize the movement of another convoy. This is not an exception to the Railway Traffic Regulations, but rather a possibility expressly contemplated for certain situations of degraded operation. This Friday, the Alternativa Ferroviaria (Alferro) union brought this circumstance to the attention of the State Railway Safety Agency (AESF) and has asked it to study the implementation of a second mandatory human verification to prevent an individual error from leading to another accident.

The warning comes nine days after the Urda tragedy (Toledo) and just three after Óscar Puente announced, in his last appearance as Minister of Transport, the implementation of a double validation system for the decisions taken by controllers when the LZB or ERTMS automatic protection systems fail. Alferro considers this measure positive, but warns that there are other railway procedures in which critical decisions can also be concentrated in a single traffic controller, without necessarily requiring a second independent verification.

Specifically, the union focuses on two procedures regulated by the Railway Traffic Regulations: supplementary telephone blocking (BT) and temporary track banalization (BTV). The first allows traffic to be managed through communications and regulatory checks when certain anomalies occur in the automatic blocking systems. The second is used to allow trains to temporarily run against the track on lines that are not normally prepared to do so.

Both procedures are subject to safety regulations and checks. However, Alferro warns that, in certain circumstances, its establishment and management may be left in the hands of a single person responsible for the control center. The regulations themselves expressly contemplate these assumptions. In the case of telephone blocking, section 4.4.2.1 of the regulations regulates its establishment under the coordination of a single person in charge while other professionals are incorporated into the affected stations. For the temporary banalization of the track, article 4.4.3.5 also contemplates that a single controller can manage certain authorizations for oncoming traffic.

The problem, according to the union, is that precisely when automatic protections stop working, human decisions take on even greater importance. Checking that a block is free, correctly identifying the last train that has circulated, determining its location or verifying that there are no incompatible authorizations are essential operations to prevent two convoys from meeting on the same section of track.

"It does not seem reasonable" that these decisions can be concentrated on a single person without a second independent verification, warns Alferro in the letter sent to the railway safety authority, to which EL MUNDO has had access.

The organization demands that, before authorizing circulation under these conditions, a second duly authorized person in charge independently checks the verifications carried out by the first. Both controls should be recorded, with identification of the professionals who carried them out, and any discrepancy would have to prevent the authorization from being issued until the situation is clarified.

It would not be necessary, according to the proposal, for both workers to be physically in the same center. The second verification could be carried out from another checkpoint or from a station, provided that there was access to reliable and sufficient information and the independence of the verification was guaranteed.

On November 2, the union had already transferred to the Traffic Safety Management of Renfe Viajeros a proposal to introduce a double check in the event of certain LZB transmission losses. That request came one day before the ministerial announcement. Now it goes one step further and demands that the AESF examine the risks of other degraded circulation procedures and that, in coordination with Adif, study the necessary changes to implement this second safety barrier throughout the railway network, regardless of the operator that provides the service.

The petition raises a question about the effective scope of the plan announced by Transportes after Urda. Puente assured on Tuesday that critical decisions made in control centers without the assistance of automatic blocking systems should be supervised by at least a second controller. However, it still needs to be specified how this validation will be applied to the different exceptional procedures contemplated by railway regulations.

Alferro insists that his proposal does not question the professionalism of those responsible for traffic nor does it imply that the current rules lack guarantees. What it calls for is to introduce an additional barrier against the possibility of individual mistakes.