page_title: North American railroad signals
section_title: Triangular color light signals
hierarchical_section_title: North American railroad signals / Signal types / Triangular color light signals
caption_attribution_description: English: Distant Signal bridge to 16th St Jct on SEPTA Main Line at North Broad station.
context_page_description: North American railroad signals generally fall into the category of multi-headed electrically lit units displaying speed-based or weak route signaling. Signals may be of the searchlight, color light, position light, or color position light types, each displaying a variety of aspects which inform the locomotive engineer of track conditions so that he or she may keep their train under control and able to stop short of any obstruction or dangerous condition.
  There is no national standard or system for railroad signaling in North America. Individual railroad corporations are free to devise their own signaling systems as long as they uphold some basic regulated safety requirements. Due to the wave of mergers that have occurred since the 1960s it is not uncommon to see a single railroad operating many different types of signaling inherited from predecessor railroads. This variety can range from simple differences of hardware to completely different rules and aspects. While there has been some recent standardization within railroads in terms of hardware and rules, diversity remains the norm.
context_section_description: Triangularly arranged color light signals consist of a cluster of three color lamp sockets in the middle of a large circular target. They were one of the first widely used type of high intensity color light signal, notably adopted by the New York Central and Seaboard Coast Line railroads, and later used exclusively by Conrail and New Jersey Transit.
  The original General Railway Signal (GRS) Type "G" design consisted of a cast iron box containing three doublet lens units in a triangular arrangement. The US&S "TR" and "TP" models used three smaller connected single lamp housings with a common background. The long defunct Chicago Signal Company had a version that used standard 5-3/8" switch lamp lenses (often of Macbeth manufacture) instead of the otherwise standard inverse-convex and stepped lens type found in the standard inner doublet design.  The Union version was later updated to a single unit akin to the GRS model. As modular color light signals have become widespread, target-type configurations have been typically offered alongside vertical type configurations. The triangular color light signal was especially useful in physically restricted and confined areas.
caption: Target style color light signals on the SEPTA Main Line northbound, just southeast of Broad St. & Lehigh Ave. in Philadelphia
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