Thanks for highlighting that @sergio and yes, @Ries it is good. It's in provincia but just walking distance from our corner of CABA. We have been several times in past years and would recommend it to anyone who is interested in that sort of thing - and even to those that aren't.
This is the only working museum I am aware of (other than the tram that goes around a few streets on weekends). At the Ferroclub volunteers restore trains and operate them on their grounds. Years ago they ran excursions. Insurance issues stopped that unfortunately.