'Triumph' in this case was the trade name of Kastner & Co., nothing to
do with the car maker!  Kastner fitted many brands of piano with the
Autopiano, but if the piano in question has no other maker listed it
may well be one of their own construction or one of the numerous
anonymous 'stencil' pianos made in London.

Triumph continued to make players into the late 1930s, including some
very small upright Art-Deco models.  After Aeolian they are probably
the next most commonly seen brand of player piano in the UK.

Sometimes these anonymous pianos have the actual maker's name pencilled
on the piano action, presumably by the action makers.  I have a piano
labelled 'Marque Ampico' (made for and sold by the Sir Herbert Marshall
piano company) that actually says 'Eavestaff' on the keyframe under the
bass keys.  That's a Herrburger-Brooks action like the one in the
query, so take the keys out and have a look!

Keith Prowse's name is seen on other brands of piano -- the Rye
Treasury has a Hupfeld Animatic-S cafe piano masquerading as a Keith
Prowse, although there the 'LH' cast in the frame gives away its
origins.

Kastner's seem to have been the sole UK agent for the Autopiano player
action; other makers had to stick with the closely-related Standard
player.  I think the Kastner Autopiano actions would have been made to
order in the USA.

Many, but not all, of the Autopiano and Standard actions seen in the
UK were fitted with Themodist-style accenting devices.  I have a copy
of the Standard service manual that has an additional section glued in
describing this device, which makes me assume it was rarely, if ever,
fitted to actions shipped in the USA.

Julian Dyer