They aren't tunnels. They're just indentations, they stop almost
immediately.
> Were they indend to be used but construction was stopped?
When Chalmers St and the surrounding area was dug up for an awfully long
time (years!) prior to the ESR actually happening, someone at least had
the sense to build both levels as stations when they did get around to
filling in the hole, in the expectation that sometime there might be a
need. Of course there have been a variety of schemes over the years (of
which perhaps the most plausible related to something fairly much in the
spirit of the new airport line) but nothing which one could regard as a
"definitive" scheme.
>. Any hidden tunnels at Town hall?
No. The only "hidden" (= never used for trains) tunnels are at St James
and North Sydney (plus fragments at Wynyard if you count the old tram
tunnels now largely used as parking space).
Eddie Oliver