"The order has a total value of around €510 million ($633 million) for the consortium," both companies said in a statement.
The two firms will modernize the control, signalling and safety equipment on the roughly 340-kilometre (211-mile) section of the high-speed line between Olmedo and Ourense in northern Spain.
The consortium is 55-percent owned by Thales with the remaining 45 percent held by Siemens.
A high-speed derailment on another section of this high-speed line in July 2013 caused 79 deaths on the outskirts of the northwestern city of Santiago de Compostela, Spain's deadliest train accident since 1944.
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