  A graph $G=(V,E)$ is word-representable if there exists a word $w$ over the
alphabet $V$ such that letters $x$ and $y$ alternate in $w$ if and only if
$(x,y)\in E$. A triangular grid graph is a subgraph of a tiling of the plane
with equilateral triangles defined by a finite number of triangles, called
cells. A subdivision of a triangular grid graph is replacing some of its cells
by plane copies of the complete graph $K_4$.
  Inspired by a recent elegant result of Akrobotu et al., who classified
word-representable triangulations of grid graphs related to convex polyominoes,
we characterize word-representable subdivisions of triangular grid graphs. A
key role in the characterization is played by smart orientations introduced by
us in this paper. As a corollary to our main result, we obtain that any
subdivision of boundary triangles in the Sierpi\'{n}ski gasket graph is
word-representable.
