Abstract: Apparatus for ultrasonic detection of flaws in the rail base of a track rail includes a sliding shoe having a transducer unit and coupling medium reservoir mounted thereon. The transducer, which is part of an ultrasonic testing system, transmits search signals into the rail base and receives associated reflected signals thereof. These signals, being capable of pictorially representing defects in the base of the rail, are monitored by the tester. The preferred embodiments allow for relative movement of the transducer unit and coupling medium reservoir along the base of the rail in order to provide for a succession of transmitted and reflected signals along the longitudinal extent of the rail base so as to test for flaws, defects, etc. in the same.

Abstract: An audio range siren detector utilizes an audio pickup including an A.G.C. amplifier, a plurality of electronic active filters having closely spaced resonant frequencies such as 800, 825, 850 timing means responsive to an actuating signal from one of the filters for generating a time slot signal of short duration, gating means responsive to each of the filter means for producing an actuating signal, control logic responsive to the occurrence of all actuating signals within the time slot to produce output denoting a valid siren signal, and relay means for setting traffic lights to emergency condition.The detector includes counters and additional timers to further restrict the conditions under which a valid siren signal will be responded to in order to better discriminate against extraneous ambient noises of all types.

Abstract: A transducer arrangement for ultrasonic rail tester coupling carriages comprising a first pair of flat angle signal transducers that are both connected to be senders and receivers and are directed in opposite directions lengthwise forwardly and rearwardly of the rail along the center of the rail head, a second pair of flat angle signal transducers that are both connected to be senders and receivers and are directly forwardly and rearwardly of the rail but are canted toward the rail gauge edge at preferred angle of 19.degree., and a third pair of flat angle signal transducers, one of which is a sender and the other of which is a receiver, that are canted toward the rail gauge edge at an angle of 80 or more degrees to provide a zig-zag signal path of multiple bounces across the rail head. The transducers act through transmitting wedges made of a material to be inefficient as a medium through which ultrasonic sound may be sent such that a significantly improved signal to noise ratio results.

Abstract: A transducer arrangement for ultrasonic rail tester coupling carriages comprising a first pair of flat angle signal transducers that are both connected to be senders and receivers and are directed in opposite directions lengthwise forwardly and rearwardly of the rail along the center of the rail head, a second pair of flat angle signal transducers that are both connected to be senders and receivers and are directly forwardly and rearwardly of the rail but are canted toward the rail gauge edge at an angle of 19.degree., and a third pair of flat angle signal transducers, one of which is a sender and the other of which is a receiver, that are canted in opposite directions toward the rail gauge edge at an angle of 80 degrees to provide a zig-zag signal path of multiple bounces across the rail head. The transducers act through transmitting wedges made of a material to be inefficient as a medium through which ultrasonic sound may be sent such that a significantly improved signal to noise ratio results.