Semiampleness on Jacobian elliptic surfaces of Kodaira dimension one

Let $π: X\to \mathbb P^1$ be a semistable Jacobian elliptic surface over $\mathbb C$, and set $χ=χ(\mathcal O_X)\ge3$, so that $κ(X)=1$. Assume that the Mordell-Weil group of $π$ is finite and that $π$ has at least one reducible fiber, the reducible fibers being of types $I_{n_1},\cdots, I_{n_s}$. R