@andresd - Welcome to BF C&V!

The pictures indicate that this is a road bike and not a track or pista bike. The deraileur drop out is the clue. The R on the fork crown is your id of a Rossin fork and likely, frame. Others will likely chime in with more information. I don't know Rossin frames or history so it will be interesting to see the responses.

A little history here: THE ORIGINS
"......Technically speaking, Garbelli’s ideas were very clear: “I have just the man we need to organise frame production - Mario Rossin – currently free. He worked for years in the Colnago welding department. He knows all the secrets of tubes and welding. He’s a wizard at measuring the athletes and making individuallytailored frames”. Mario Rossin, from Cavenago in Brianza, with Verona origins, was immediately involved in the project. And on 14 September, 1974, Rossin offi cially saw the light in Cavenago. 5 partners were involved in the project: Vittorio Ghezzi and his son Giuseppe, then Inzaghi, Garbelli and Rossin. “The bikes will be called Rossin”, agree Inzaghi, the Ghezzis, father and son, and Domenico."

BTW: Very nice frame with some interesting features like the chain stay bridge substitute!