{"id":"S85111030","label":"Railroads--Signaling--Block system","description":"","source_url":"https://id.loc.gov/authorities/subjects/sh85111030","normalized_label":"railroads--signaling--block system","broader":[],"aliases":["Block-signal systems"],"source_identifier":"http://id.loc.gov/authorities/subjects/sh85111030","provider":"lcsh","revision":"9c93e1f896b3f719","taxonomy_revision":"f050b5d4780b1289","title":"Railroads--Signaling--Block system","url":"/topics/S85111030","kind":"topic-directory","aeo_cohort":"topic-directory","catalogue_revision":"f050b5d4780b1289","numeric_address":"10090526347375018564","address_version":"morton4x16-v1","coordinates":[0,20,19139,55296],"answer_status":"Directory metadata; local answer requires separate source review","truth_status":"Subject descriptor, not a factual answer or a demonstrated knowledge gap","reviewed_answer":null}