Check out the GoKunming article: Around Town: Kunming's new and improved Railway Museum
The museum has expanded and now also has a nice section on China's High Speed Train System, including a mock-up of the inside of a HS train.
The museum is closed (until 2015 because of the subway construction) the only place you can still visit is the shed, which is really amazing, you can sit in wagons one century old and be amazed at some ancient looking steam locos built in the 1880s that were still in use in Yunnan ten years ago
the entrance is free and it really deserves a visit. I'm really disappointed about the real museum though...
To find the shed just follow the tracks left of the museum, it will be on your right just before the entrance of a residence As has been stated before : it's hidden behind a tree, so look out for trees :)
A great find for us history minded folks with plenty of artifacts, stories, and best of all, the actual train engines themselves (the centerpiece of any train museum). The presentation is on par with the exhibits at the Smithsonian, and almost everything is bilingual, meaning that you don't have to be able to read Chinese in order to understand what the photos and objects in front of you are and why they are memorable. Highly recommended for anyone who enjoys history or trains in general.
If you take your time and read everything, it'll take you over an hour to go through the exhibits, meaning that your 10 yuan will be well spent. Just be aware that the shed with the engines themselves is located down the road from the front of the museum in an apartment complex, so it took us two tries to find it. To avoid our mistake, make sure you go down the road past the rail crossing and then look on your right side for a small open square where the shed will be. Thanks to a tree blocking the view from the road, the sign is not easily noticeable.
Went today for the second time... I'd forgotten how many good old photos there are of old Kunming as well as smaller cities that had stations like Hekou, Kaiyuan, Mengzi, etc.
Bombarded the staff with questions and they did everything they could to answer them. Nice folks.
You don't have to be a trainspotter to enjoy this museum. It is in two parts; the main musuem with a wealth of detail about the Vietnam-Kunming railway and, some way off, a shed with some beautiful ancient locomotives. Well worth 10 yuan