DONALD R LITTLE
Engineers in Greensburg, PA

4932615, Jun 12, 1990

Oct 12, 1988

7/256894

Marvin J. Frazier - Roselle IL
Donald R. Little - Greensburg PA

Electric Power Research Institute - Palo Alto CA

G08B 2900, B61L 2100

246121

A railroad track segment simulator for assessing track signal susceptibility to electric power line interference including a circuit including a series dc resistor, a series inductor, and an inductive network representing characteristic impedance of an electrical R-L transmission line, resistor, inductor, and network being serially connected as a series circuit, a first ballast resistance connected between one end of series circuit and a ground potential, and a second ballast resistance connected between another end of series circuit and a ground potential. The impedance of the segment is expressed as: ##EQU1## where: f=frequency (hz), r. sub. o =effective radius of rail at power line ac frequencies=0. 09 m for 132 lb/yd rail, R. sub. dc =dc resistance per kft of track, j=imaginary number, Ln=impedance per track segment.

4297548, Oct 27, 1981

Dec 19, 1979

6/105354

Donald R. Little - Greensburg PA

American Standard Inc. - Swissvale PA

H01H 3500

200 6108

A vital incidental relative movement monitor assembly including a support member and a carrier ring member which is screw-threaded into the support member. The carrier ring member includes an apertured annular flange which is concentric with an apertured annular flange formed on the support member. An indexing wire is threaded through the apertured annular flanges for retaining a carrier ring member relative to the support member, and an electrical monitoring conductor also threaded through the apertured annular flanges for disrupting an electrical circuit when incidental relative movement occurs between the carrier ring member and the support member.