Podcast Summary: "El sindicato de maquinistas señala un 'déficit de mantenimiento' en las vías de alta velocidad liberalizadas"

Podcast: Más de uno
Host: Onda Cero (Carlos Alsina)
Guest: Diego Martín Fernández (Secretario General, SEMAF)
Date: January 20, 2026

Overview

In this episode, Carlos Alsina interviews Diego Martín Fernández, Secretary General of the Sindicato de Maquinistas (SEMAF), about the recent derailment on the high-speed rail lines and the ongoing investigation. The conversation delves into possible causes of the accident, maintenance practices on liberalized high-speed lines, prior union warnings, and the practical realities faced by train operators. The tone remains factual, professional, and at times urgent due to the safety implications.

Key Discussion Points and Insights

1. Current Investigation and Hypotheses ([00:00]–[01:34])

• The interview begins with Alsina asking about current hypotheses for the derailment, mentioning reports of a piece of rail (30–40 cm) possibly failing due to a welding issue.

• Union’s Stance: Diego stresses SEMAF’s reliance on professional investigators and calls for independence and autonomy in reporting accident causes.

  • "No es descartable ninguna [hipótesis]...Lo que queremos es que exista la autonomía y la independencia…de esos informes que después se publiquen. Y eso es lo que nosotros reivindicamos..." (B, [00:41])

• Diego emphasizes the importance of discovering the true causes, not just for accountability but to prevent future tragedies, referencing the importance of transparency given the presence of victims.

2. Protocols and Response of Train Operators ([01:34]–[03:25])

• Alsina asks about the reaction and awareness of the train crew during the incident.

• Operator Actions: Diego explains the procedures strictly followed by the train operators, including emergency braking and subsequent checks, and mentions that operators reacted "de manera ejemplar" (in an exemplary way).

  • "Actuaron de manera ejemplar según los procedimientos..." (B, [01:59])

• Awareness During Incident: He notes that in high-speed accidents, operators are rarely immediately aware of the full consequences; the impact unfolds in seconds and real assessment happens once the train is stopped.

  • "Es raro que en el mismo momento...te puedas dar cuenta de las consecuencias...es cuando realmente puedes valorar la situación." (B, [03:02])

3. SEMAF’s Warnings About Vibrations and Infrastructure ([03:25]–[05:11])

• The host references a previous SEMAF report warning about increased vibrations in high-speed train lines due to greater traffic following liberalization.

• Nature of Vibrations: Diego attributes increased vibrations to higher traffic and insufficient preventative maintenance, not immediately to safety issues but to greater wear-and-tear affecting comfort and potentially leading to more breakdowns.

  • "En esas líneas se venían observando mayores irregularidades, mayores vibraciones y menor actuación preventiva..." (B, [04:01])

• He stresses their warnings aimed to improve maintenance for both passenger comfort and worker safety.

4. Safety Implications and Threshold for Service Suspension ([05:11]–[05:44])

• Alsina presses whether these vibrations could lead to accidents.
• Threshold for Action: Diego underscores that SEMAF has previously lobbied for service suspension when they considered infrastructure unsafe; however, in this case, they did not deem the network fundamentally unsafe—but believed maintenance measures required improvement.
  • "En este caso nosotros no consideramos que la vía es insegura... existía un déficit o unos procedimientos de mantenimiento que podían mejorarse." (B, [05:11])

5. Technical Factors: Vibration’s Role in the Accident ([05:44]–[07:20])

• The host suggests a possible link between vibrations and weakening of weld joints (soldaduras).

• Union’s Limitations: Diego admits they are not engineering experts and ultimate conclusions must rest with technical reports and independent investigators.

  • "Nosotros no somos expertos en ingeniería de materiales... eso lo tendrá que establecer el informe y los peritos y los técnicos..." (B, [06:06])

• He reiterates the call for transparent investigation so lessons can be learned and future accidents prevented.

• Explanation for Increased Vibrations: Diego points again to the higher traffic volume and unchanged maintenance regimes—comparing it to a road enduring ten times more vehicles but maintained at the same level.

  • "Si tú mantienes igual que cuando tenías menos volumen... aumenta el desgaste y aumentan las vibraciones..." (B, [06:45])

6. Technical Details: Rail Wear vs. Road Wear ([07:20]–[08:14])

• Alsina draws a parallel between rail and road wear. Diego explains that railways experience even greater impact due to the metal-to-metal interface and heavy inertia of trains.

  • "El sistema ferroviario... es metal contra metal... Existen muchísimas más inercias, muchísimas toneladas, lo que pesa un tren. Y eso produce muchísimos desgastes..." (B, [07:35])

• He calls for a shift from focus on building new infrastructure to prioritizing ongoing, robust maintenance of existing lines.

Notable Quotes and Memorable Moments

• Call for Transparency and Independence:
  "Lo que queremos es que exista la autonomía y la independencia…de esos informes que después se publiquen." — Diego Martín Fernández ([00:41])

• On Operator Response:
  "Actuaron de manera ejemplar según los procedimientos..." — Diego Martín Fernández ([01:59])

• On Maintenance Deficit:
  "Existía un déficit o unos procedimientos de mantenimiento que podían mejorarse y podría ocurrir." — Diego Martín Fernández ([05:11])

• On the Wear-and-Tear Cycle:
  "Si tú mantienes igual que cuando tenías menos volumen, pues al final aumenta el desgaste y aumentan las vibraciones..." — Diego Martín Fernández ([06:45])

• Rail vs. Road Wear:
  "Es metal contra metal el tren contra la vía y existen muchísimas más inercias, muchísimas toneladas, lo que pesa un tren. Y eso produce muchísimos desgastes..." — Diego Martín Fernández ([07:35])

Timestamps for Key Segments

• 0:00–1:34 — Introduction, current accident hypotheses, and union’s demands for investigation independence
• 1:34–3:25 — Train operator protocols during accidents and awareness
• 3:25–5:11 — References to prior union warnings and the issue of vibrations
• 5:11–5:44 — Safety implications vs. maintenance recommendations
• 5:44–7:20 — Exploring technical links between vibrations and failures, union’s perspective
• 7:20–8:14 — Detailed explanation of rail wear, comparison with highways, and maintenance advocacy

Conclusion

Diego Martín Fernández, on behalf of SEMAF, stresses the union’s long-standing concerns about insufficient preventative maintenance on increasingly busy high-speed rail lines, clarifies actions and protocols by train crew during emergencies, and repeatedly calls for transparent, expert-led investigation into the recent tragic derailment. His remarks reflect the tension between comfort, reliability, and safety—and urge a shift in infrastructure priorities from expansion to robust, ongoing maintenance.

Listen to this episode for an in-depth, insider perspective on rail safety, union advocacy, and what’s at stake for both workers and passengers in Spain’s high-speed rail era.