Editing Multiple unit (section)

==History==
[[File:South Side Elevated Railroad car 1.jpg|thumb|South Side Elevated Railroad car #1—one of the cars that Frank Sprague converted to MU operation in Chicago]]

Multiple-unit train control was first used in [[electric multiple unit]]s in the 1890s.

The [[Liverpool Overhead Railway]] opened in 1893 with two-car electric multiple units,<ref>{{cite web |url=http://www.liverpoolmuseums.org.uk/mol/collections/transport/overheadrailway.aspx |title=Liverpool Overhead Railway Motor Coach Number 3, 1892 |quote=This is one of the original motor coaches which has electric motors mounted beneath the floor, a driving cab at one end and third-class accommodation with wooden seats. |publisher=[[National Museums Liverpool]] |access-date=21 January 2011 }}</ref> controllers in cabs at both ends directly controlling the traction current to motors on both cars.<ref>{{cite web |url=https://www.nytimes.com/1902/01/18/archives/mr-sprague-answers-mr-westinghouse.html |title=Mr Sprague answers Mr Westinghouse |date=18 January 1902 |access-date=16 June 2012 |first=Frank |last=Sprague |author-link=Frank Sprague |website=[[The New York Times]] }}</ref>

The multiple-unit traction control system was developed by [[Frank J. Sprague|Frank Sprague]] and first applied and tested on the [[South Side Elevated Railroad]] (now part of the [[Chicago 'L']]) in 1897. In 1895, derived from his company's invention and production of direct-current elevator control systems, Frank Sprague invented a multiple-unit controller for electric train operation. This accelerated the construction of electric-traction railways and trolley systems worldwide. Each car of the train has its own traction motors: by means of motor control relays in each car energized by train-line wires from the front car, all the traction motors in the train are controlled in unison.