Signaling Fault Disrupts São Paulo’s Linha 4-Amarela, Buses Deployed as Service Gradually Recovers

Overview

• ViaQuatro reported a signaling-system instability around 4:40 a.m., reduced train speeds for safety and activated the PAESE emergency bus plan about 4:55 a.m.
• Support buses were slow to arrive at several stations, with TV Globo observing first deployments near 6:20 a.m., and at least one passenger fainted during crowding and received SAMU care.
• The operator initially requested 24 buses and later added 10 more, totaling 34 vehicles to cover the Luz–Vila Sônia corridor.
• Transfers at Paulista–Pernambucanas, República, Luz and Pinheiros were closed to control flow and were later reopened as service was restored.
• ViaQuatro says trains never stopped and ran at reduced speed, a claim disputed by riders and reporters; more than 100 staff were mobilized, an investigation is underway and official delay declarations are available on the operator’s website.