This gives some impression of the unbelievable gradient the Tua line trains had to surmount to get out of the Douro Valley. And the climb continued for several miles before they settled on a ledge cut into the east side of the Tua Valley as shown in the shot of E82 two days ago.
The train used to back up as far as it could go and then charge through the station to take a run at the bank. There was a NG pilot at Tua, usually a small 0-6-0T and it used to bank the train if it was much longer than this one. I have seen it with up to 20!
The broad gauge line in the bottom RHC is the Douro line from Porto to Barca d’Alva. It’s level!