The Metro Bilbao system consists of three metro lines. It has been in operation since 1995 and the system is a bit over 43 kilometres long. All trains are made by CAF and they were made in three series, UT-500, UT-550 and UT-600.
Picture from the Casco Viejo metro station in Bilbao 4.5.2013 by Ilkka Siissalo.

A class UT-550 train no. 558 is approaching the Casco Viejo station. This train series has been in use since 2001 and it was delivered by CAF and Adtranz.
Picture from the Casco Viejo metro station in Bilbao 4.5.2013 by Ilkka Siissalo.

Side view of the same train no. 558.
Picture from the Casco Viejo metro station in Bilbao 4.5.2013 by Ilkka Siissalo.

This metro train no.519 is from the first series UT-500 from 1996. There are 24 trains of this first series in use. Note that metro trains in Bilbao do not get their electricity from a third rail as usual, but rather from a catenary overhead wire. The operating current is 1,5 kV DC.
Picture from the Casco Viejo metro station in Bilbao 4.5.2013 by Ilkka Siissalo.

A series 2100 metro train on line L4 stopping at the station Jaume I.
Picture 7.11.2011 by Ilkka Siissalo.

Another series 2100 metro train on line L4 stopping at the station El Maresme.
Picture 9.11.2011 by Ilkka Siissalo.

One of the same series 2100 trains now in 2024: The trains have been repainted with a new scheme. This train is on line L4 Trinitat Nova - La Pau.
Picture 7.11.2024 by Petteri Holopainen.

Side view of a series 4000 metro train of Barcelona. The operator is TMB, Ferrocarril Metropolitano Transversal de Barcelona.
Picture from the station Glòries 14.11.15 by Ilkka Siissalo.

A series 5000 metro train on line L5 is stopping at the station Hospital Clinic.
Picture 6.11.2024 by Petteri Holopainen.

A series 6000 metro train of TMB, built by the company CAF. These are the currently the most modern trains on Barcelona's metro line L1.
Picture from the station Glòries 14.11.15 by Ilkka Siissalo.

A series 7000 metro train on line L3. Line L3 is the so called Zona Universitària - Trinitat Nova line, often referred to as the green line. It has a 1200V DC electric current overhead on a rigid electricity rail in the tunnel ceiling.
Picture 7.11.2024 by Petteri Holopainen.

People getting in and out of a line L1 metro train of the type series 6000.
Picture from the Santa Eulalia metro station in Barcelona 14.11.2015 by Ilkka Siissalo.

A series 6000 metro train of TMB stopping at the station of Sagrera.
Picture 14.11.15 by Ilkka Siissalo.

One of the series 9000 metro trains built by Alstom on Barcelona's line L4.
Picture from the Jaume I station 7.11.2011 by Ilkka Siissalo.