The British Rail Class 333 electric multiple units were built by Siemens and CAF are based on the Class 332 trains operated by Heathrow Express.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/32038338@N02">Peter Broster</a>
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/remedy451/8061892873/">Siemens Class 333 No 333013</a>