Transport Research International Documentation (TRID) https://trid.trb.org/ en-us Copyright © 2026. National Academy of Sciences. All rights reserved. http://blogs.law.harvard.edu/tech/rss tris-trb@nas.edu (Bill McLeod) tris-trb@nas.edu (Bill McLeod) Transport Research International Documentation (TRID) https://trid.trb.org/Images/PageHeader-wTitle.jpg https://trid.trb.org/ USE OF VIBRATING BLADES OR PITCH CONTROLLERS FOR SIGNALLING PURPOSES https://trid.trb.org/View/87229 Tue, 31 Jul 1979 00:00:00 GMT https://trid.trb.org/View/87229 RAILROAD ACCIDENT REPORT, SIDE COLLISION OF SOUTHERN RAILWAY COMPANY TRAINS NOS. 1 AND 152, SPENCER, NORTH CAROLINA, OCTOBER 8, 1977 https://trid.trb.org/View/75592 Tue, 31 Oct 1978 00:00:00 GMT https://trid.trb.org/View/75592 SIGNALLING...WITHOUT POLE LINES? https://trid.trb.org/View/71866 Wed, 29 Mar 1978 00:00:00 GMT https://trid.trb.org/View/71866 THE EFFECT OF HARMONIC OSCILLATION IN POWER SUPPLY AND AUDIO-FREQUENCY REMOTE CONTROL SYSTEMS ON RAILWAY LIGHT SIGNALS https://trid.trb.org/View/60502 Fri, 13 Jan 1978 00:00:00 GMT https://trid.trb.org/View/60502 COORDINATION OF TRAFFIC SIGNALS WITH RAILROAD GRADE CROSSING PROTECTION https://trid.trb.org/View/66440 Wed, 16 Feb 1977 00:00:00 GMT https://trid.trb.org/View/66440 ELECTRICAL NOISE: GET IT OUT OF THE SIGNAL PLANT https://trid.trb.org/View/39250 Sat, 24 Jul 1976 00:00:00 GMT https://trid.trb.org/View/39250