The bonus with these lightweights is that they are a lot more forgiving and don't need to have the heavy duty steel rails in use today. They can reliably function on rails made from timber such as those used for mining carts in the 16th & 17th century and even for rail into the 19th century as witnessed in the photo below from New Zealand.
Source of image:
http://nzetc.victoria.ac.nz/tm/schol...6Rail029a.html
For more info, there's a decent report of early rail lines at the following wiki link.
https://en.wikipedia.org/wiki/Permanent_way_(history)