  This research contains as a main result the prove that every Chordal
$B_1$-EPG graph is simultaneously in the graph classes VPT and EPT. In
addition, we describe structures that must be present in any $B_1$-EPG graph
which does not admit a Helly-$B_1$-EPG representation. In particular, this
paper presents some features of non-trivial families of graphs properly
contained in Helly-$B_1$ EPG, namely Bipartite, Block, Cactus and Line of
Bipartite graphs.
