TP&W #501-506 look to be a shortened bay window caboose. They date from 1940 and were originally numbered 201-206. TP&W #521-522 were built in 1954 and have the half bay window like on the New York Central cabooses of the time. TP&W #524 was rebuilt to #528. It has a full bay window and was built in 1956.
Ed