Since 1991 this has been the end of the Uckfield branch line. Until then it continued past the signal box and over a level crossing to a station on the opposite side of the road and, even earlier than that, onwards to Lewes.
<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>