Renfe Class 730
The Renfe Class 730 or S-730 (Spanish: Serie 730 de Renfe, manufacturer's designation Talgo 250 Dual) is a high-speed dual-gauge, dual-voltage and hybrid (electric and diesel) trainset consisting of 11 Talgo VII tilting coaches and two power cars, used on Alvia services. The class have been nicknamed "patitos" (ducklings/little ducks), due to the shape of the train nose. They are a variant of RENFE Class 130 modified to be able to run on both electric and diesel power, in order to extend higher-quality services to parts of Spain not on the  electrified network. Background and design. The trainsets are designed for high-speed services on conventional Iberian gauge () network and standard-gauge high-speed () lines; they can change gauge at low speed without stopping using Talgo's RD variable gauge system. The carriages are constructed from aluminium and incorporate the "Talgo Pendular "passive pendulum tilting system, are sealed against pressure differences for tunnel travel, and have underframe air conditioning, individual audio systems and video displays, rotating and reclining seats and power outlets. Capacity in standard class is 36 seated, in first class 26 seats, end coaches have lower capacity, one coach  is typically used for restaurant/sales services. The power cars use AC traction motors controlled by IGBT inverters which include integrated auxiliary inverters. Signalling systems can include ETCS Level 2, LZB, ASFA and Ebicab900TBS. 2013 Santiago de Compostela accident. On 24 July 2013 a Renfe Class S730 running as the Alvia 4155 service from Madrid to Ferrol derailed and crashed near Santiago de Compostela in north-western Spain, killing 78, out of 218 passengers on board. The cause of the accident is not yet officially determined, but the train was alleged to be traveling over twice the posted speed limit  while entering a curve, due to the absence of ERTMS.