No it is not as there were 2 separate cement works Swanscombe and Northfleet the tunnels under the hot rod diner used to to be the main entrance to the cement works my dad said as there used to be security there and the Swanscombe line would of run from the Eastern Quarry now castle hill down to the marshes where the cement works were then onto the jetty on the marshes the jetty is still there abandoned just not found A way onto it yet cause it is like A fortress literallyCould it be part of the same line that runs under the hotrod dinner