Released a few days ago, Train Simulator 2013 has not had an easy way to figure out the locomotives you get in the base package. Railsimulator team posted a rolling stock album at Facebook so new users will have a better overview of the content.
Other customers using Train Simulator 2012 can upgrade for free. Take care of your actual expansions and third party addons installed though, backup them first !
For more expansions, browse Railworks section at simMarket.