This is a Talgo II set (Design of 1955, by American Car Foundry), more sophisticated than the Design of 1949 (Talgo-ACF) which RENFE used from 1950 to 1972.
This Talgo set was built for the New York, New Haven & Hartford Railroad in 1956, and ran on the Shore Line (New York-Boston) from 1957 to around 1960, as a commercial experiment. The core idea was to test various lightweight trains (Talgo, Train X, Aerotrain...), with a view to purchasing 30 to 40 sets of the best-proven type.
Sadly, the sharp downturn in passenger mainline traffic which occured in the late-50s nipped all those bright plans in the bud.
After some years of idleness of various sidings, the whole NH fleet was sold to the Ferrocarril de Langreo (Spain), a private Railway focused on Coal and Iron Ore Trains from Laviana to Gijon (Asturias).
This was the only non-urban Spanish railway built to standard gauge (1435mm-4ft8in), which often led this company to look for second-hand rolling-stock from the US.
The NH fleet consisted in 5 3-car sets. These were bi-directional, unlike the Design of 1949, and were very close to Talgo III of 1964 in many aspects. Both end cars had one wheelset only, whereas the intermediate car had two of these, as current TC7z-706 or AVE-102 40x Cafeteria cars.
The whole NH fleet was shipped to Gijon in late-1964.
Unfortunately, those cars had been designed by ACF for America only, and thus encroached into Talgo Patentes SA rights on Talgo wheelsets in Spain.
So, in order not to pay any royalties to Talgo, the Ferrocarril de Langreo had to look for a substitute system. So, it ordered single-axle, Schienenbus-style trucks from MAN, which one can very easily notice on that pic.
All in all, those second-hand Talgo trains were used well below their potential, taking some 2 hours just to run over 50km of derelict tracks, while DMUs were faster. In 1973, the FC de Langreo was absorbed by FEVE, which rebuilt the Gijon-Laviana line to metric-gauge in 1983.
Most of the fleet was then sold to individuals, who have used them as second homes or for farming.
Only one set was preserved for a while, on some sidings in Gijon. Unfortunately, it wholly went up in smoke in the mid-80s, as an executory for enraged shipyard workers....
This pic was taken at some time in the 70s. Carbodies were already in a declining condition.
Photo by J. Aranguren (Acknowledgements). Posting and comment by P.L.Guillemin (plguillemin@yahoo.fr)