710 261 in sidings at Willesden Junction station showing an East London line destination (New Cross Gate) that these trains will not normally serve - and indeed it would be illegal for them to travel to via the tunnel under the River Thames because these trains do not have emergency exits at the train ends.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/47739225@N08">citytransportinfo</a>
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/citytransportinfo/40457674253/">710261-WillsJcn-Sidings-S3050016</a>