T gauge (1:450 or 1:480) is a model railway scale with a track gauge of 3 mm (0.118 in), referred from "Three-millimeter gauge" or "Third of N scale". It was introduced at the Tokyo Toy Show in 2006 by KK Eishindo of Japan, and went on sale in 2007. It is the smallest commercial model train scale in the world. Since mid-2009, Railway Shop (Hong Kong) is the exclusive licensed manufacturer.
Wikipedia

Now Cameron Turner is our resident expert on T(iny) Gauge trains.
Many of our Train Expo Visitors will recognize his work on the littlest layout at the show.
Here are some videos of it over the years so you can see its progress and enjoy it.

Inaugural Run
Running at the Central Train Show (February 2018)
2019 T Gauge at Central Train Show
2020 T Central Layout Update

Here you can find a lot of in progress shots of Cameron's work, as well as his thoughts about railroading and a lot of great stuff in his blog.