This one is INSIDE the tunnel. Your GPS will not work in here, however it is bang in between two other caches:
GCAFA9 Once Were Trains
and
GC2JRPV cachie me if you can (Update 4 Apr 2018 - this cache was archived some time ago.
You will need a torch and your own pen.
As metioned, your GPS will not work inside the tunnel, but the following should place you right on to the Berocca tube.
In the tunnel heading toward Maymorn there are three 'service alcoves' on the left. The cache is 8m from the third and final alcove between ankle and knee height.
Congratulations to the following....
FTF - Barnaby's Travels
2TF - Juice box
3TF - MAC42