>Metre-gauge tram and driving trailer R6 on mixed-gauge track, same location as photo c0833, on bridge over the RENFE line, BarcelonaAs I said, notice one pole on each car. Also, barely intelligible, the tram has a sign in the front that says "completo" = complete, as in full. Hard times.
This bridge was pretty new at this time, before that the trams crossed a level crossing. Since the bridge was built around the same time this rail line was electrified (to be precise this is the branch to acces Estación de Francia, the big terminus station that's still in service), my guess is that it was done because the level crossing did not allow wires to cross. At other places there remained tram and train level crossings, and the trams had to speed through without overhead wire. At least on one occasion a train crashed into a tram that didn't make it across.
The area has changed a lot, but this place is easily found because of the bridge:
https://www.google.es/maps/@41.3951301,2.1896147,3a,75y,29.28h,88.97t/data=!3m6!1e1!3m4!1sxPvcUMcQC3AHdtMiQioy8g!2e0!7i13312!8i6656 