On 14 Jun, 15:28, Mystery Flyer wrote:
Isnt signalling supposed to make such things impossible? Im quite
ignorant here of the technicalities of the ability of the line
controller to manually over-ride things etc but in my ignorance I
assumed the signalling was all automatic based on some giant
computerised timetable...

If everything works as planned, the signalling should prevent it.
However, railway signalling is designed to prevent *unsafe* situations
from arising. A train ending up on the wrong route isn't really
unsafe, merely inconvenient (with certain exceptions, for example if
the train is too large to fit into a tunnel).

In this case, it's possible that a signaller pressed the wrong button,
or that the train was carrying an incorrect description at the control
room. The driver will receive an indication of which route is set, but
it's quite easy for him not to notice that the wrong indication is
displayed - especially somewhere like Camden Town. We don't know why
the wrong route was set, and AFAIK we also don't know if the driver
had queried it and been told to continue in order to save time. None
of this is unsafe in itself, though it will cause delay and
inconvenience to passengers. In essence, it shouldn't happen, but
human nature means mistakes will occasionally happen and we just have
to learn to deal with it.