I served on a ship for 4 years and I've been on 2 ocean liners. Never has the place where food is prepared been called a "caboose".

Merriam Webster defines caboose as a ship's galley. My Oxford English Concise Dictionary (1977) defines it as a "Cooking-room on ship's deck" (photo of entry available upon request).

https://www.merriam-webster.com/dictionary/caboose

According to Wikipedia, if an "authoritative source," is "caboose" derived from the obsolete German word "kabuse" (circa 1300-1600) for a small cabin on a sailing ship. The Dutch later formed the word "kabhuis" (circa 1747) for the small cabin on a sailing ship to prepare the meals, and modern Dutch evolved the word as "kombuis."

The first locomotive was in 1804, so the caboose on a train is named after these small cabins on sailing ships.

https://en.wikipedia.org/wiki/Caboose#Etymology

Agree with Laredo7, 12 years at sea and definitely never heard the
galley called that................served on 6 different ships.

If you follow up on enough references (follow the footnotes at the Wikipedia link above), you will see that the term is obsolete - used several centuries ago, and therefore used as a reference for a train carriage that was also used for food preparation. The train caboose evolved different functions, and the shipboard one had a change of name, but the historical link was definitely there.

Here is some clarification from the Wikipedia definition:

A caboose is a small ship's kitchen, or galley, located on an open deck. At one time a small kitchen was called a caboose if aboard a merchantman, but a galley aboard a warship.

https://en.wikipedia.org/wiki/Caboose_(ship's_galley)

It's almost as obsolete as "ocean liners."

I dont think the (ship) term is quite obsolete in English, although the item may be!

Here it is being used in the 21st century talking about a 19th century Thoreau piece which in turn describes an 18th century item.

https://www.capecodtimes.com/story/news/2007/10/06/thoreau-leads-clifford-to-whydah/52776837007/