First and only rack railway museum
Korenov is about 15-20 mins away from Harrachov and it is easy way by car. If you want to be really spontainious, you shou definitely go by train.
Museum itself is located at the old train station and it is quite unique. Whole exposition is dedicated to the piece of railway between Tanvald and Szklarska Poreba (PL). There are original racks as well as old trains. This is very unique experience.