BH Tower, Walton: Thoughts on Mr. Gordon's Photo of the CTC Machine

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Mr. Stone suggests:

>>>  I believe you mean the reverse. Signal levers have three positions and
lamps (left, off, and right) while switch levers have two (normal and
reverse).   <<<


Yup,  I said it back-ards, Larry.  Good catch on your part.  Mea culpa.  I
need to double my daily dosage of Geritol.

SWITCH levers have only two indications for a reason:  Should the switch
points "hang up" in mid-travel, or should the lock rod fail to complete its
stroke and lock the operating rod, the designers want the indication to "go
dark."    If the switch is locked either Normal or Reverse, you will get an
indication.  But if it fails to lock either Normal or Reverse, there is no
indication.  That was just the logic of the signal engineers.  (Locking,
and the types of locking, is one of the most interesting studies in the
field of signaling.)

SIGNAL levers, on the other hand, have a three indications:  L, R, and a
third indication at the top, always Red, in my experience.  If a proceed
signal were not displayed either L or R, the red lamp above the Signal
lever would light.    So you could walk into a tower and with one glance at
the board, tell if the operator was "pulled up" for any trains.   If all
the "reds" were lit above the signal lever row, nothing was moving on the
territory.  Drawing on 30 year old memories, I believe even this red lamp
would extinguish would during the interval between the instant a control
code was sent out and the instant an indication code was received back,
which, depending on how busy the code line was, could take ten seconds or
more.

I believe some similar convention is observed in the "modern"
train-dispatching-by-computer thingie.  Switches flash on the monitor, if I
remember correctly, until the lock indication is received back from the
field.  And the route over which a signal is requested, turns yellow on the
monitor until the indication reports back that the signal is displayed in
the field, at which time the trace on the monitor turns green. Or some such
permutation.  But I have tried to forget all that modern stuff, as I never
really enjoyed working with it.

Attached is a photo of some switch and signal levers on my Union Switch &
Signal CTC machine, which was built in 1938.  The photo shows the
arrangement of the indication lamps.  The color of the jewels (called "lamp
caps" in the materials catalog) was up to the railroad ordering the
machine.  I believed the N&W used white jewels for a lot of the indications
on its CTC machines, but I don't recall which ones.

And, BTW, I just checked a photo of the US&S CTC machine from Limedale,
Indiana, which is supposed to have been US&S's first CTC machine.  It is
now owned by a friend of mine, and is a decade or more older than my 1938
machine.  The photo of Limedale shows that the arrangement of indication
lamps over Switch and Signal levers is identical to the photo I am
attaching.

One further comment on this subject, concerning Signal levers.  Any good
operator puts the Signal lever back "on center"  (i.e. straight up)
promptly after a movement is completed.  This prevents the accidental
display of the signal later on, should he accidentally hit the code start
button.  I never saw the requirement to do this explicitly stated in any
railroad rule books, but I was involved in investigating one situation
where a CTC operator got in very serious trouble by failing to restore a
Signal lever to "center" after a move had been completed.  In the Walton
photo, all the Signal levers not being used appear to have been placed back
"on center."

One lesson I have learned in "doing history" is,  "Never say, 'never'."
Just about every time you give a generalized answer, someone will come up
with an exception to the norm.  And the N&W had a few practices which were
unconventional to the signal industry, and I have never understood why they
would want to deviate from the collective experience of the industry,
 which was hammered out on the anvil of trial-and-error.  Perhaps it was a
case of someone's vanity.  We have all seen senior managers who just have
to make some tiny change in an otherwise bulletproof plan, just to leave
their mark.

Attachment.

-- abram burnett


Moderator:

http://www.nwhs.org/mailinglist/2017/20170428.001_CD%20CTCMachine_Levers.jpg

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