North American railroad signals

（重定向自Approach signal）

Baltimore and Ohio Railroad color position lights on bracket masts at Magnolia, West Virginia

A stacked searchlight dwarf signal at Springfield, Massachusetts

A Pennsylvania Railroad position light signal bridge with replacement mast signals in the background. The design of steam locomotives meant that all signals had to be placed to the right of the running track. Current diesel engine design allows both left- and right-hand siting.

A semaphore signal on the Atchison, Topeka and Santa Fe Railway in 1943

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.

单词	Approach signal
释义	Approach signal 英语百科 North American railroad signals （重定向自Approach signal） 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.
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