In message
-septe
mber.org, at 22:13:51 on Fri, 24 Mar 2017, Recliner
remarked:

Unlike the Gatwick shuttle, there are points, so trains can switch track,
and the number of trains isnt limited to two.

In both cases like the shuttle at Stansted, or thinking back a long way
the inter-terminal shuttle at DFW back in the 80's. May be still there.
--
Roland Perry