Museum was created in an old steam depot founded in late XIX, and keeps the original buildings and facilities like roundhouse, water depots, .... so you will have more to see than only locomotives.
Entering the main building there is a video-projection room where you can see restored films and documentaries, and many railway related artifacts and devices. The following photo is the interlocking table used in Barcelona's "Estació de França" in 1929.
Outdoors there's a huge collection of steam locomotives completing 180º of the roundhouse. It's a huge collection of HUGE locomotives, with some versions of Mikados and Mastodonts with more of 3.000 CV and wheels taller than me.
There are also newer locomotives like 7800 series "Panchorga" built in USA, 7001 series "Chata", Crocodile, and our most charming and nostalgic train in Spain "Talgo":
But there is a very small locomotive well preserved inside the roundhouse which is very special for me: "La Caldes". It's the oldest locomotive built in Spain with its syster 0232 manufactured by "La Maquinista Terrestre y Marítima" for the Barcelona-Sarrià railway. When the "Ferrocarriles de Catalunya Company" acquired, electrified and narrowed the line, both locomotives where sold to the Mollet-Caldes de Montbui railway, passing through my native town. My grandmother used that train and when I was a child she told me very funny stories about its slowness. They were able to jump out the train, pick some blackberries and get on it again. Finally, the bus service provoked that small line to disappear before I was born.
There are also some old maintenance vehicles, like this Landrover ready to run on the railways:
Finally, the activity of that Sunday was the running of Mataró 1-1-1 locomotive that you can see in the following video: