On 07/06/2010 10:45, David Hansen wrote:
On Mon, 7 Jun 2010 02:29:14 -0700 (PDT) someone who may be dave
wrote this:-


What has failed a fair few times is the new electric points at Praed
Street!

Interesting to know. An earlier poster said that it may be new
equipment which is more prone to failure.

I am reminded of the axle counters around the Severn Tunnel which
couldn't cope with sunshine, leading to repeated failures and
eventually a crash which appears to have been caused by the axle
counters being reset without proper precautions (though this cannot
be concluded as the witch-hunt atmosphere of the time (lessened but
not totally gone these days I gather) meant that people are not
likely to admit to mistakes).

Obviously old signalling equipment could and can be affected by the
sun too, but rodding runs have ways of dealing with this and wire
adjusters are provided for signals.



New equipment may very well be more prone to failure because there tends
to be far more to go wrong. There was (in some places still is!) the
old Victorian technology of someone pulling levers connected to wires
connected to signals, also simple telegraph instruments and single
stroke bells to communicate. Compare this with the "black art" of the
modern electronic signalling systems with a maze of processors,
communication links and detection systems which can be the devil's own
game to "troubleshoot".

Add to this the likelihood that any problems may be less obvious to the
users - the old technology could largely be "seen". This is why many
people will go to things like the mechanical organ museum in Norfolk -
you can see the exhibits working and in many cases how they work. In
future years, who is going to go to a museum to watch a board of
integrated circuits sit there?

Don't get me wrong - technology is great and the job I do is so much
better now than with the antiquated kit we used to have to use. But
discretion is required - it is a general rule that the simplest solution
that does the job is also the best one.

New technology should not automatically replace the old - it should give
us more choice. Where the old way is reliable and does the job safely
and efficiently, why throw it away? I have often thought that some of
the older signalling technologies might actually serve the railway
better than going too far down the fancy computer systems road,
precisely because the modern stuff can be too complex and too vulnerable.

Axle counters are a very good example. They are replacing track
circuits because axle counters are allegedly more reliable. But when
someone has on overnight possession [for engineering work], the track
circuits are normally still working in the morning but the axle counters
invariably have to be re-set. This requires either the first train or
two being "talked past" signals to restore the settings, or the whole
system being reset which means nothing moves for a few minutes. And its
not just sunlight - track workers in the Bournemouth area were given
strict instructions not to use mobile phones near the new axle counter
heads because that also confused the signalling.

I'm all for progress - but progress means that the new kit must work
*better* than the old stuff did. If it is harder to use, more difficult
to fault find, breaks down more, and exhibits its own new ways of going
wrong, I'm afraid that's not "progress". I know of more than one modern
system which has been introduced mostly to save on (staff) costs, and if
it actually works better than before (in the case of Network Rail's new
timetable system, if it works at all!), that seems to be a bonus.

--
- Yokel -

Yokel posts via a spam-trap account which is not read