Let (X, r) be any set-theoretical non-degenerate solution of the Yang-Baxter equation and (X, r) be the derived solution of (X, r). As for any braided vector space (W X,r , c) associated to (X, r), is it possible to find some braided vector space (W X,r , c) which is t-equivalent to (W X,r , c)? In case that (X, r) is a near-rack solution, we give a sufficient condition to make an affirmative answer to the question. Examples of t-equivalence are constructed, hence finite dimensional Nichols algebras are obtained. In particular, all finite dimensional Nichols algebras associated to involutive near-rack solutions are classified.