Here is some pictures.
http://www.klondyke.co.uk/files/imag.../brookside.jpg
This one is of central station:
http://static.panoramio.com/photos/original/7719035.jpg
http://farm4.static.flickr.com/3517/...335aca6427.jpg
http://farm3.static.flickr.com/2552/...84b48d3a9c.jpg
PS: the second part of the description should include another tunnel AFTER the third station as well as the one before.
The above pic shows this.
The website has not been updated to show the extension so still says the line is half a mile.
Please note that tickets can only be obtained at central station (also known as brookside/ brookside central and poynton brookside and then the other stations can be used when wished.