"Vernon" wrote in message
...
I have several relatives who have, at different times, been on the new
Southern trains (on the Brighton/Portsmouth line) when all the doors have
stuck.

Is this a common problem? Is the cause known but too expensive to sort?
Has
anyone addressed the issue of what could result if it coincided with a
fire?

Doors have been a recurring problem with what are termed "plug-type" doors
since they were first introduced at the beginning of the 1990s. It's
generally to do with getting the pressure correct on all the door sets so
that the door, when closed, sucks in to the bodyside and is held there, so
that the door interlock (central door locking) can be activated by the
driver or guard to secure the train.

The doors can appear to be set correctly when on a depot or works but once
the train is subjected to curving and reverse curving, banking etc. the
bodysides can flex very slightly - but enough to throw out the door
adjustments. Similarly, when stopping on slightly banked tracks in stations
the "throw" of the train can upset the delicate adjustment.

Generally, after a period in traffic, the doors have been adjusted and
readjusted until they are at their optimum setting. The Electrostar trains
are still being introduced on Southern services, several new units per week,
and are still going through their shakedown period in service. From
experience with all other units over the past fifteen years it is to be
expected that the majority of the problems will gradually disappear,
although occasional problems with individual door sets still occasionally
occur. There should be no safety inplications in the case of fire - the
problems are most often with securing the doors, rather than releasing them.
There is a manual override for freeing the doors, in addition to the
emergency door releases in each vestibule.