Sooner or later, you might take a job that will require you and your family to move. You will likely incur significant expenses in the process, and if you are like most people, you will want your employer to pay for at least some of them. The following advice should help you handle this negotiation as effectively as possible. Focus on Your Interests
The Railroad Caboose. For more than a century the railroad caboose was a fixture on the end of freight trains. The real purpose of the caboose was to provide a sheltered vantage point from which trainmen could watch the cars ahead, sleep, cook and eat their meals, and do their paperwork. It served as the working headquarters of the freight conductor and his rear brakeman.
I have never heard of this expression before but I'm guess it refers to the fact that nowadays trains use digital signals instead and as a result they don't have caboose/brake van anymore. So (without context), it probably means that the person who said it believed that caboose is important and safer than digital signals? Or the trains will be safer to have a live human being watch out for it ?