Category talk:Rolling stock innovations

Vehicles only?
WP needs a category for innovative rolling stock, but some innovative rolling stock has no separate article. Sometimes, the system was innovative, introducing a new kind of traction or a new supply. Perhaps a "category:Railway innovations" would be better, if innovative rolling stock is admitted.--Ulamm (talk) 01:16, 23 December 2013 (UTC)
 * What are the criteria to list a specific article in this category? For example, what is innovative about the SJ Rc locomotive you added? I'm afraid this list could really become huge, and has a considerable overlap with the Experimental locomotives category. --Aaron-Tripel (talk) 09:39, 23 December 2013 (UTC)