Looking along platform 4 at Crystal Palace station where it is beneath the ticket office and concourse. Electric unit 377136 is just emerging from the tunnel to run into platform 2 on its way to Beckenham Junction.
<a href="//commons.wikimedia.org/wiki/User:Geof_Sheppard" title="User:Geof Sheppard">Geof Sheppard</a>
CC BY-SA 4.0
<span class="int-own-work" lang="en">Own work</span>