The signal is red. In this situation the red light shows that a train recently has passed towards the photographer.
<a href="//commons.wikimedia.org/w/index.php?title=User:Fomalhaut&amp;action=edit&amp;redlink=1" class="new" title="User:Fomalhaut (page does not exist)">Fomalhaut76</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>