That term certainly makes sense since intra means within, but I'm from
the east coast and I've never heard the term in the 50 or so years I've
been involved with the fire service. Having said that, I have to admit
I'm not very interested in the apparatus, only in the fires they
fight.:)
Another observation. Someone used the term "wagon" to describe Engine
12s spare. Back in Boston a wagon is (was) a hose wagon. Boston had
quite a few in the 50s and 60s, but they were gradually phased out. The
most notable was Engine 26s wagon that had 3 deck guns on it. For the
doubting Thomases, I have photos.
Also, at that time every Cambridge engine company was a double company -
pump and wagon.
Finally, the photo on the Portland fire web site is out of date. After
the 7 Pierce pumps arrive, we will completely update the site. It will
take some time before all the apparatus re-assignments are finished,
but it will be done.