A signal at the Hubertushof junction west of Düren (on Cologne-Aachen)
seen from a train passing eastbound on 27 April 2002. As there were
construction works going on, the train had to change to the left track. The
signal could not show the normal proceed aspect in this case, so the Zs1
(substitution signal) was given (yes, it was a Zs1, not a Zs8, that looks the
same except that the white lights are blinking).
<p>
Digital photo by
<a href="http://www-users.rwth-aachen.de/christoph.schmitz2/index.html">Christoph
Schmitz</a>