The decision to exercise the option, which is worth around €500m, is due to be approved at a meeting of the Renfe board next month.
In November 2016 Renfe awarded Talgo a €786m contract to supply 15 trains and maintain the fleet for 30 years.
Delivery of the initial batch is due to begin in 2019, with the second tranche arriving from 2021 onwards.
Each train will seat 521 passengers with 80% of seating in tourist class, where there will be a 3+2 layout, and 20% in business class, which will feature a 2+2 seating configuration. All seats will be adjustable to face the direction of travel and equipped with LED screens in the headrests.
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