[ Ref. 240912 MMDigest

I've found more on the Hesper Mabel Steam Calliope fire. The biggest
source was a YouTube video of the calliope playing on the show
grounds just prior to the parade during which the fire occurred.

Video #1: https://www.youtube.com/watch?v=zSUvOULvSSY
 
Hesper - Mabel Steam Engine Days 2024 Celebration: Steam Calliope
plays on the Grounds; Calliopist Eric Heukeshoven plays a medley
including "Way Down Upon a Swanee River" and more.

With YouTube "Settings" you can run the video at 1/4 speed. This
video shows that two liquid propane (LP) tanks were carried in two
garbage cans at the rear of the wagon, one on each side:
https://youtu.be/zSUvOULvSSY?t=108 

The boiler appears to be an antique coal-fired  boiler, but how
the propane burner(s) were installed is outside the video screen.
There are many hoses used to make connections.

A video from June of this year shows the same boiler being fired
with coal:

Video #2: https://www.youtube.com/watch?v=N77vT7Wdmq4
 
Spirit of Winona: Winona's Steam Calliope - Winona State University
Digital Collections

Another webpage says:

"Rachel Storlie, a professor at Luther College Music Department,
plays the Hesper-Mabel Steam Calliope at Nordic Fest in Decorah, Iowa.
Harry Shell built this circus wagon in the early 1900s and installed
the whistles and valves with a boiler inside the wagon. 32 whistles are
chromatically tuned (loosely speaking), starting with C below middle C,
and operate at 50 psi of steam pressure. Learn more about this Calliope
and find more organ music on
Pipedreams: https://www.facebook.com/steamenginedays/ "

This instrument is not a mechanical music machine. It uses manually
operated valves with wire connections [to the keyboard].

In contrast, six of the steam calliopes which played at the Steam
Calliope Rally at the International Circus Hall of Fame in 2023, were
mechanized. They used solenoid valves and were controlled through MIDI
interfaces. To play manually they used MIDI keyboards with extension
cables. This fits within air calliope tradition which had paper rolls
and pneumatic keyboards.

About 40 seconds into Video #1 you can see that the left propane
cylinder is connected to a regulator with about 3 feet of black hose.
This hose is unprotected and apparently carrying full tank pressure.
The routing of the black hose from the regulator is unclear.

The right tank has another black hose to a regulator and a hose rising
to the top of the wagon as part of its connections. About 50 seconds
in we see the boiler attendant climb into the rear to adjust valves.
At about 1:50 we get a second look at the plumbing.

My guess is that during the parade someone, or something, fell on one
of the rubber hoses and broke a connection. This could have released
a stream of propane directly into the boiler compartment which was then
ignited by the boiler fire. The fire would then have burned until the
tank was empty. The fire engine's water didn't stop the propane fire,
it just kept the metal cooler and put out burning wood of the wagon.

We all could offer lots of advice about how the installation might have
been improved, but I think they are well aware of the corrections
needed.

Wallace Venable
Morgantown, West Virginia

[ Much propane information is at https://en.wikipedia.org/wiki/Propane 
[ -- Robbie