  The aim of the present article is to give an exact and correct representation
of the essentially important part of modern special relativity theory that
touches upon the behavior of the proper length of accelerated moving bodies.In
particular we pointed out that standard solution of the Bell's problem
[3]-[4]revision needed. Classical solution of the relativistic length expansion
in general accelerated system completely revisited.Instant proper length
measurement between J.S.Bell's rockets also is considered successfully.
