(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)