Locomotive Cranes

In the opening years of the twentieth century Fairbanks-Morse listed
locomotive cranes among products made. Has anyone seen, or
know of the existence, of any of these units on any rail carrier
(regardless, of prime mover engine type), at any point in time?

Or at any point, on any form of operation (i.e. industrial, or marine)
as well as common carrier?
Thank You, pjb

Do you mean a "self propelled" type of crane, or a track mounted crane, like those found in the backshops, of larger engine servicing facilities?

Locomotive Cranes are self propelled cranes by definition,
sometimes called wreck or relief cranes,- and colloquially "Big Hooks".

They come in the form of single boom or double boom
(a/k/a tunnel cranes). The latter always had
swivelling booms with fixed power plant(s) for operating the traction
engine(s) as well as the booms, as far as I can tell.
That is; the dual boom units did not have integral rotating
steam (or I.C.) powerplant that swivelled with
crane boom(s), which allowed them to operate in areas
where movement was restricted. Hence the moniker
"tunnel cranes", and their ownership by operators like
New York Central System for use on restricted spaces found
by their urban lines (e.g. CUT, NYC suburban zones, etc.).
Good-Luck, PJB