Nothing at all to do with the Algarve, but if you like videos of old Portugal and steam trains this will tick both boxes.  It's 9 minutes 32 seconds.

I stumbled across this one on Youtube. There is no date but the line was closed to passengers in 1981, so that's the last possible.  It shows a mixed passenger and goods train making its way through the countryside, loading and unloading at various stops. Passengers travelled in the blue railcar being towed along at the back of the train.

http://www.youtube.com/watch?v=D6VtpW50_no" rel="nofollow - https://www.youtube.com/watch?v=D6VtpW50_no

There is a longer, 32 minute, video at http://www.youtube.com/watch?v=gqJ3T3W4qEw" rel="nofollow - https://www.youtube.com/watch?v=gqJ3T3W4qEw dated 1980 but with vehicles that look as if they came from the 1880's! There is more emphasis on the trains themselves in this one.

The Linha do Sabor was a metre gauge (1000mm) line up in the north east of Portugal that ran from Pochino, the current terminus of the Douro Valley line) up into the hills for 102km to nowhere in particular. Originally started in 1917 to reach an iron ore mine, it was never finished. It had an active life of about 60 years.

https://en.wikipedia.org/wiki/Sabor_line" rel="nofollow - Wikipedia item.