For some reason Turkey’s “premier” railway museum is basically in the middle of nowhere. Its in a village called Çamlık which is so small I think the museum has more trains than it has houses. Best way to get there is by train from Selçuk, which is about 9km away, of which there are several throughout the day. Selçuk is also the best place to base yourself to visit the ruins at Ephesus so its not like you are heading there just for the trains. Its then a short to the museum from Çamlık’s station (the museum is actually by the site of the old station.) If you are feeling ambitious and want to cycle it, bear in mind its up a steep climb.
It was 5TL to get in, excellent value and I had the place basically to myself. Its really nicely laid out although the trees are in great position for photographing. Highlights are a carriage used by Ataturk, with bedroom and bath, and the steam plough used to rescue the Orient Express in 1929 which inspired Agatha Christie to write “Murder on the Orient Express.”
If you do go, much more useful information on the museum can be found here.