First of all, accept my apologies for not writing in Portuguese, my knowledge of your language is unfortunately much too weak...
I recently visited the Tua line: It is the only scenic narrow gauge line for which all the infrastructure is basically still in place to allow some kind of railway operation. The other line, the Vouga line, is not as beautiful as far as the scenery is concerned and is still operated by CP. Other lines have been dismantled (Corgo being the last one).
In many other European countries, private volunteer organisations operate scenic trains, so why not in Portugal?
The first step is to make a call for railway enthusiasts to set up an organisation and collect funds. Then you could buy a second hand diesel to operate some trains with selected cars from the ones that are standing in Tua station, following an agreement with the infrastructure owner (REFER).
The second step should be to contact an other European organisation that operates narrow gauge steam engines and have an agreement with them to operate one of their steam engines on the Tua line. HSB (Wernigerode, Germany) is the best to my eyes for that purpose. All steam engines in Portugal are beyond repair and none is in state good enough to be put on steam. So a foreign loco is required.
Interested partners should be:
- - Mirandela authorithies (the train would attract tourist to Mirandela)
- - CP (the Tua tourist train would complemente their own Regua-Tua "comboio histórico"
- - Owners of businesses in Tua station and along the line (The train would attract clients)
- - "Rabelos" operators on the Douro river (idem).
Hope my suggestion will attract someone's attention.
Lover of the Douro region and of scenic trains.