The slope inequality for families in the trigonal locus

Let $g$ be even, let $B$ be a base curve not entirely contained in the Maroni divisor, and let $X\to B$ be a family whose singular members belong only to $\Delta_0\mathfrak{T}_g\cup\Delta_{1,i}\mathfrak{T}_g$. The slope inequality. The slope satisfies

$$\frac{\delta}{\lambda}\leq 7+\frac{6}{g}.$$

This gives a bound for the slope of such families in the trigonal locus, under the stated restriction on the singular members and the Maroni divisor. The source supplies no resolution status beyond its presentation as a proposition.