Western Railroad Discussion > Signal Placement Question

Those of you familiar with the BNSF Topeka sub know they are converting it from ABS to CTC. This past summer there were lots of men and equipment around Lawrence (Ks.) as Lawrence was apparently their staging area. All that’s gone now. Either the project is finished or they moved to the area south of Topeka. They made one more signal change in the Lawrence area last week that kind of baffled me.

In case you aren’t familiar with this area the BNSF follows the Kansas River from Kansas City to Topeka. The river has lots of turns between KC and Topeka, and so does the railroad. At Lawrence the river turns and runs north and south for a couple of miles. At the far north end of Lawrence, where the river turns and resumes it’s east-west orientation, there was a west bound signal just before the curve. I always thought from a safety standpoint it was smart to have that signal there to protect that 90 degree curve. Who knows what might be out of sight around the curve?

Last week they took that signal down. The present configuration now is there is a westbound signal just east of the Lawrence Amtrak station. There’s a couple of little curves west of the depot, then a mile and a half or so of straight (north-south) track and then the track curves and heads west again. I don’t know where the next signal is west of the curve, but it’s got to be a least 2 miles from the previous signal east of the station.

My questions: (1) does removal of the signal before the curve create safety issues? (2) does the distance, and fact that the next signal is obscured by curves, create safety issues?

Thanks for your help.

As train lengths have increased, signal blocks have increased to 2-3 mile spacing between signals. Each railroad has its own preferences and standards.

Hard to visualize the area you are describing. A major part of signal placement is ensuring the signal is visible from a sufficient distance that a train crew can see and react to a signal safely. For example, you don't want a train coming around a corner and suddenly getting a stop indication. That would result in an emergency stop or the train passing the signal. The spacing of signals also depends on the location of sidings, the track speed, etc.



Edited 1 time(s). Last edit at 11/22/17 07:16 by hotrail.

hotrail Wrote:
-------------------------------------------------------
> Hard to visualize the area you are describing. A
> major part of signal placement is ensuring the
> signal is visible from a sufficient distance that
> a train crew can see and react to a signal safely.
> For example, you don't want a train coming around
> a corner and suddenly getting a stop indication.
> That would result in an emergency stop or the
> train passing the signal. The spacing of signals
> also depends on the location of sidings, the track
> speed, etc.

Exactly correct. Signal spacing has been dictated by the
normal stopping distance for the fastest, and heaviest
trains expected on the line segment.

There is supposed to be something called territory familiarity that each crew should have in their possession prior to running over territory.

As long as the signal move was announced via general order in advance of the change the crews should be able to adjust to the new signal locations.


As for curves usually signals are aimed so you can see them before getting right on top of them, usually.

For safety well restricted speed and absolute stop indications should take care of that.

Should.

Posted from iPhone

Yes a General order was issued that gave all that pertinent information.

CTC was cut in from Lawrence to Tecumseh on Sunday. They have now moved west and will be working on Pauline to Osage City which will be cut in in 2 sections later this year. Topeka will be the last as there is a proposal to completely reconfigure the east end of the Topeka yard eliminating the interlocking of the old Atchison main.

Posted from iPhone



Edited 1 time(s). Last edit at 11/22/17 08:26 by SantaFe.

Signals, generally speaking, are placed at the bottom of hills, just around a curve for maximum difficulty in seeing.

These gentlemen are correct in that the signal system still protects the trains and crews. And the crews are notified of changes in signal placement. If the signal that you can't find ism red the preceding signal indicates the track is vacant to the next signal which is red. If the signal that you described is red then the train would be trailing at restricted speed to the next signal if permitted.

Bob Krieger
Cheyenne, WY

Several things govern signal placement, the most important things being track speed, location of switches or crossings/junctions to be protected. Signals are not intended to provide protection for speed on curves. What color would 20 mph be? How about 30? How about 50?

There won't be an emergency stop as mentioned above, because of the way signal systems are designed. At least, a signal system will display Green, then Yellow, and then Red Aspects, which (in GCOR) are described as Proceed, Approach, and Stop. In newer territories, a Flashing Yellow, or Advance Approach indication is added.

A Flashing Yellow requires an immediate speed reduction (depending upon the individual railroad,) and passing the Yellow at not over 30, "prepared to stop before any part of train or engine passes next signal." So, the train approaching a Red signal is expecting it to be Red as soon as it passes the Yellow in front of it, is familiar with its territory, and is operating accordingly.

On the former WP Feather River Canyon, there are several Absolute Signals that are not visible for more that FOUR CAR Lengths! These are due to the sharp curves and the steep canyon walls. Their Mickey Mouse signal system still provides advance warnings, a yellow over lunar, if the next signal is a facing point switch and the signal is either yellow to go down the main, or Red over Yellow to go in the siding. A solid yellow will be displayed on the last signal before coming around a corner expecting a Red.
G

I second imrl's statement!!

PWM

On the Shasta Route in the Sacramento River Canyon in Calif, signal placement has been changed in the last few years to quite long spacing with PTC. Track speed is 25 mph and train length upgrade is generally restricted by the curve at the infamous Cantara Loop. The rather numerous Union signals have been removed and in most places 3 sets of old signals have been replaced by just one set of lights between sidings. Spacing now varies from about 1.5 to over 2 miles on low speed track that is mostly curves with minimal sight distance ahead. All I can think is the crew will be depending on PTC to warn them of slides and other hazards as signals are few and far between. The slide warning signals are generally gone.

Lol

imrl Wrote:
-------------------------------------------------------
> Signals, generally speaking, are placed at the
> bottom of hills, just around a curve for maximum
> difficulty in seeing.

Posted from iPhone

> Signals, generally speaking, are placed at the
> bottom of hills, just around a curve for maximum
> difficulty in seeing.

You left out "on the other side of overpasses".

EtoinShrdlu Wrote:
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> > Signals, generally speaking, are placed at the
> > bottom of hills, just around a curve for
> maximum
> > difficulty in seeing.
>
> You left out "on the other side of overpasses".

Being close to a grade crossing seems to be the primary concern in the last decade or so.
That way the signal maintainer does not have to walk far. Whether it is in a good
spot from the engineer's point of view does not seem to matter anymore. I have seen
many moved from where they previously could be seen for miles to a point at the end
of a curve just so they could be by a road crossing.

Englewood Wrote:
-------------------------------------------------------
> EtoinShrdlu Wrote:
> --------------------------------------------------
> -----
> > > Signals, generally speaking, are placed at
> the
> > > bottom of hills, just around a curve for
> > maximum
> > > difficulty in seeing.
> >
> > You left out "on the other side of overpasses".
>
> Being close to a grade crossing seems to be the
> primary concern in the last decade or so.
> That way the signal maintainer does not have to
> walk far. Whether it is in a good
> spot from the engineer's point of view does not
> seem to matter anymore. I have seen
> many moved from where they previously could be
> seen for miles to a point at the end
> of a curve just so they could be by a road
> crossing.

Another is just beyond a road crossing at a control point / interlocking rather than including the crossing in the interlocking. It is much easier to design the interlocking if there is no crossing within the interlocking limits. Of course, every train that is approaching the red signal needlessly activates the crossing signals until it comes to a stop, causing drivers to get used to false activations and start ignoring the signals. Then we blame drivers for ignoring crossing signals. Were the crossing within the interlocking, it would be behind the red signal and would not be activated by a train approaching the red signal in the process of stopping

TAW

TAW Wrote:
-------------------------------------------------------
> Another is just beyond a road crossing at a
> control point / interlocking rather than including
> the crossing in the interlocking. It is much
> easier to design the interlocking if there is no
> crossing within the interlocking limits. Of
> course, every train that is approaching the red
> signal needlessly activates the crossing signals
> until it comes to a stop, causing drivers to get
> used to false activations and start ignoring the
> signals. Then we blame drivers for ignoring
> crossing signals. Were the crossing within the
> interlocking, it would be behind the red signal
> and would not be activated by a train approaching
> the red signal in the process of stopping
>

Exactly.
One of the first interlockings I worked, Washington Heights,
had the gates on the Pennsy Panhandle set up properly.
Gates would not go down if signal was not cleared. If train was
in the crossing approach when the signal lever was reversed
the signal did not clear until gates were down. Of course those
crossing circuits were probably designed in the 1940's when things
were much easier to do with relays and miles of wire instead of computers.

The present "better way" has been around for at least 20 years. I had one
spot where trains were routinely held out of the yard. About 5000' fit
between crossings. So big trains approached the crossing very slowly as they
snugged up to the signal which was just before the crossing. The crossing was
wired the modern way so the gates were down on a MAJOR city street while the
agonizing process worked out.

One time a train got right up super tight to the signal and the gates would not
go up. Either the predictor or island circuit was screwed up. I got into it
hot and heavy with the signal department "leader" when he came storming into the
office about the train being too close. I told him the train was not even by the
signal, so the gates should not be down. He asked me if I was a signal engineer.
I told him no, but I have been around long enough to know how things should work
and his **** was ****** up. Then the Chief stepped in and got between us.

This was the same fool that had the "code line failure alarm" on the Digicon set
at 3 minutes to cover up his half a** code line that was run from what looked like a CB
antenna on top of the office.



Edited 1 time(s). Last edit at 11/25/17 06:16 by Englewood.