Editing Multiple-unit train control (section)

==Origins==
[[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===
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]]| accessdate=2011-01-21 }}</ref> controllers in cabs at both ends directly controlling the traction current to motors on both cars.<ref>{{cite news|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|accessdate=16 June 2012|author=Frank Sprague|author-link=Frank Sprague|work=[[New York Times]]}}</ref>

===Frank J. Sprague===
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 of the traction motors in the train are controlled in unison.