Why were the original IMR codes retained when the Northern Line cabins
were closed and the IMRs linked to Cobourg Street? Wouldn't it have
been simpler to re-plate everything in the 'N' series?

In article .com,
TheOneKEA writes
Why were the original IMR codes retained when the Northern Line cabins
were closed and the IMRs linked to Cobourg Street? Wouldn't it have
been simpler to re-plate everything in the 'N' series?

Why go to the effort of re-plating, re-drawing all the circuit diagrams,
changing all the manuals, ...? What's wrong with the present numbering?

--
Clive D.W. Feather | Home:
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Clive D. W. Feather wrote:

Why go to the effort of re-plating, re-drawing all the circuit
diagrams, changing all the manuals, ...? What's wrong with the
present numbering?

The use of single-letter codes, compared to double-letter codes
everywhere else (even on the same line!) seems a bit inconsistent to
me. Admittedly, as long as everyone knows what everyone else is talking
about, it boils down to a minor nit, but just the same it seems odd to
see signals plated "G5" for example.

"Clive D. W. Feather" wrote in message ...
In article .com,
TheOneKEA writes
Why were the original IMR codes retained when the Northern Line cabins
were closed and the IMRs linked to Cobourg Street? Wouldn't it have
been simpler to re-plate everything in the 'N' series?

Why go to the effort of re-plating, re-drawing all the circuit diagrams,
changing all the manuals, ...? What's wrong with the present numbering?

Circuit prints don't show the area code, just the signal number. G5
signal's circuitry for instance would have the circuit title 5G, and
its signal relay would be 5GR. Saying that, as every sheet would have
"INTERLOCKING MACHINE ROOM 'G' - GOLDERS GREEN"
at the top the process to change every master by hand could get a bit
labourious.

Thomas Crame wrote:

Circuit prints don't show the area code, just the signal number. G5
signal's circuitry for instance would have the circuit title 5G, and
its signal relay would be 5GR. Saying that, as every sheet would have
"INTERLOCKING MACHINE ROOM 'G' - GOLDERS GREEN"
at the top the process to change every master by hand could get a bit
labourious.

Wow, I never knew that the signal codes were that extensive!

In article . com,
(TheOneKEA) wrote:

Thomas Crame wrote:

Circuit prints don't show the area code, just the signal number. G5
signal's circuitry for instance would have the circuit title 5G, and
its signal relay would be 5GR. Saying that, as every sheet would have
"INTERLOCKING MACHINE ROOM 'G' - GOLDERS GREEN"
at the top the process to change every master by hand could get a bit
labourious.

Wow, I never knew that the signal codes were that extensive!


and of course that's just the tip of the iceberg. Changes would also have
to be made to the:
signal diagram display panel in the IMRs
panel in the control room at Cobourg St, the signalman's desks
"controlled diagrams"
technical support's diagrams
line supplements
training notes and presentations
staff handouts and other materials
local working instructions
Trackernet
95 stock simulator
signalman's desk simulator
etc. etc.
(and this is just a few!)

Granted, many of the changes above would not have been necessary in the
30s because a lot of the items would not have been around then in the way
they are now.

Technical advances over the years has meant that much can be done with
computers including diagrams and text related work. This has spawned many
items that are now issued to trainstaff, used as reference, used as
training materials etc. I am currently involved using Powerpoint to
simulate signal clearance when trains are approaching a controlled area.
Changes to a signal number could affect anything up to a 100 slides! Other
than these presentations, there are probably around 20 things that I have
created and maintain that would need changing if a controlled signal
number was changed. These include booklets and diagrams which are issued
to staff or used as reference/training material.

There is also the actual cost involved of having somebody get down on the
track and change the signal plate. In these days of what is effectively
privatisation, each department has their own charges and seemingly minor
jobs can cost from several hundred to tens of thousands of pounds.

A few years ago, it was decided to relable most of the "X" signals on the
Northern Line to "A" signals so that they could be treated as an automatic
signal and not a semi-automatic signal with the subsequent delays that
could cause. Because of the cost, it was decided not to change any station
starters that were an "X" as there would normally be a delay if the signal
remained at danger anyway. Therefore, it wouldn't be cost effective to
make the change.

Roger
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