Oil produced from Sperm Whales is indeed still useful stuff, but not a
practical fueld for steam engines beyone toy models.
Just to note in passing, one of the larger uses for whale oil today is
to lubricate the electro-mechanical tone generators in older model
Hammond Organs. I also use it as fuel for the oil lamps in my
sailboat.
It's expensive, but it burns cleanly and doesn't readily evaporate.
Still, it would be terrible waste to use it to power a steam engine of
any useful size.
Harry C.