What's the difference between caboose and coboose?

Caboose

Definition:

(n.) A house on deck, where the cooking is done; -- commonly called the galley.
(n.) A car used on freight or construction trains for brakemen, workmen, etc.; a tool car.

Example Sentences:

(1) I’m going to give this award, but black people will not ride the caboose of society and we will not bring up the rear any more.” “I want you to recognise us.” In the 27 years that have passed Murphy hasn’t won an Oscar.
(2) Fog creeping into the cabooses of collier-brigs; fog lying out on the yards and hovering in the rigging of great ships; fog drooping on the gunwales of barges and small boats.
(3) I just want you to know that black people will not ride the caboose of society or bring up the rear any more.” Over a quarter of a century later, we have utterly failed to meet those demands.
(4) Thus health services are located where the most profits can be generated rather than community need--a caboose following the general economy.