As originally used on Glasgows  underground railway after its conversion from cable haulage to electricity.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/61132483@N00">Les Chatfield</a> from Brighton, England
CC BY 2.0
<p><a rel="nofollow" class="external text" href="https://www.flickr.com/photos/61132483@N00/785786450/">Glasgow Corporation electric loco</a>
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<ul><li>Uploaded by <a href="//commons.wikimedia.org/wiki/User:Oxyman" title="User:Oxyman">oxyman</a></li></ul>