Train Basics Ask Trains ‘X’ locomotive number

‘X’ locomotive number

By Angela Cotey | April 15, 2018

| Last updated on November 3, 2020

Ask Trains from the February 2016 issue

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Southern Pacific cab-forward 4-8-8-2 No. 4219 leads an extra train at Dunsmuir, Calif., in August 1948.
Guy L. Dunscomb, Martin E. Hansen collection
Q On some early Union Pacific and Southern Pacific steam and diesel locomotives there is an “X” in front of the number. Why is this done? – Leon Bassik, Langhorne, Pa.

A Trains on some railroads, such as Union Pacific and Southern Pacific, would display the train number on the lead locomotive. When an extra (non-timetable) train was called, the crew would place an “X” in the engine’s train indicator box, ahead of the locomotive number. Thus if locomotive No. 4219 was assigned to an extra train, the number board would read “X-4219.” This would tell any other train crew that this train was not one of the regularly scheduled trains listed in the timetable. – Martin E. Hansen

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