[Code of Federal Regulations] [Title 49, Volume 4] [Revised as of October 1, 2005] From the U.S. Government Printing Office via GPO Access [CITE: 49CFR235.5] [Page 580] TITLE 49--TRANSPORTATION CHAPTER II--FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION PART 235_INSTRUCTIONS GOVERNING APPLICATIONS FOR APPROVAL OF A DISCONTINUANCE OR MATERIAL MODIFICATION OF A SIGNAL SYSTEM OR RELIEF FROM THE REQUIREMENTS OF PART 236--Table of Contents Sec. 235.5 Changes requiring filing of application. (a) Except as provided in Sec. 235.7, applications shall be filed to cover the following: (1) The discontinuance of a block signal system, interlocking, traffic control system, automatic train stop, train control, or cab signal system or other similar appliance or device; (2) The decrease of the limits of a block signal system, interlocking, traffic control system, automatic train stop, train control, or cab signal system; or (3) The modification of a block signal system, interlocking, traffic control system, automatic train stop, train control, or cab signal system. (b) [Reserved] (Approved by the Office of Management and Budget under control number 2130-0042)