Roanoke Junction - NELSON'S CROSSOVER

[NW Mailing List]

Joe Shaw, Ron, Abe, et.al.
 
Let me first say that my comments about the Nelson Crossover and the interlocking plant around Park Street are from my perspective as a brakeman /conductor on the yard for 30 years. My time does not make me an expert as a signalman. I am not a signalman, so from a technical viewpoint, I could be dead wrong. My observations are strictly from an operations standpoint with what little bit I might have picked up otherwise.
 
Furthermore, I made my comments more from the historical aspect of identifying the crossover and the source of it's name and not from the standpoint of explaining the circuitry of signal operations. For that job I am uniquely UN-qualified.
 
I have attached two images which may help show how the tracks departing the Forwarding Yard and Park St. Yard finally merge at the Park Street signals. These are looking west. These images were made a number of years ago by an anonymous photographer who was apparently a C&E employee who snapped these as he entered the yard on a westbound train. They were posted on-line, so many of you may have seen/downloaded them. My thanks to the photographer for sharing them.
 
The track to the right(north) in these images, is Main 2 (WBML). This track is signaled all the way through the Terminal. The track next to it is the Westbound Running Track(WBRT) which comes off the Park St. ladder and continues all the way east to, just west of, N. Jefferson St. It is used by the Delivery Crews who switch their cars at Park St. Yard. Trains leaving or entering the yard (Main 1 or 2) can move on either side without interfering with their switching.
 
You can see that the Forwarding Yard ladder(2nd track from left/south) splits and either ends in the Old Eastbound Main Line(Main 1, to the south), or into the WBRT(center track). So, at the Park St. signals there are only three tracks. 
 
If you are westbound on the WBRT you can go three directions: 1) through a crossover to Main 2(north side): 2) up the Running Track to Park St. ladder; 3) to the Forwarding Yard ladder. There is actually another crossover between the FY ladder and the WBRT, used principally to make moves between Main 1 and the WBRT.
 
Movements on the Old Eastbound Main Line(OEBML, Main 1) can move westward up the OEBML, or through a crossover to the Forwarding Yard ladder, and, possibly through the other crossover to the WBRT. Then, of course there is the Nelson Crossover between the FY ladder and the OEBML(Main1).
 
I hope I haven't confused things more!
 
Jeff Sanders
 
 
 



On Friday, October 11, 2013 9:00 AM, NW Mailing List <nw-mailing-list at nwhs.org> wrote:
  

My understanding is that the 'old main line' (east) end of the Nelson
Crossover is electrically locked, since it is inside of the Park Street
control point. The west end of the crossover on the Forwarding Yard
ladder is outside of the control point, so can be a simple hand-throw
crossover.

In Ron Davis's photograph of the non-so-new derail by the VMT,
http://nwhs.org/wiki/show_image.php?id=570,
the track closest to the VMT is the "Old Main Line". The derail is a
dispatcher controled powered derail, protected by a signal behind
the photographer. The crossover switch beyond the derail appears to
be electrically locked. Notice that it does not have the simple
green/yellow target stand like the switch for the west (near) end of
the crossover. The dwarf signal on the crossover protect movements
into the interlocking.

I was under the impression that the dwarf was a dispatcher controlled
signal, but based on Mr. Sander's comments I may be incorrect on that,
Most other instances of electrically locked switches I know about do
not have signals on the associated track, so this setup is rare.

The next track to the left is the Forwarding Yard ladder. The switch
machine visible in the foreground is for a just out of sight power
switch to track 6. The first visible turnout is the hand throw
switch for the west end of the crossover. Note that does not have a
large flat black box like the forward switch machine.  The second
visible turnout is the power switch that leads to the (sub-)ladder
for forwarding yard tracks 7, 8 and 9.  On that sub-ladder is visible
a power switch for track 7 (the closest route).

At the far end of the Forwarding Yard ladder track at the very top of
the picture is a crossover between the ladder and the second track from
the left. (Is that track considered main 1 at this point? )  The track
on the farthest left is Main 2.  Out of sight off the top of the photo
are two signals for the Forwarding Yard Ladder track and the maybe-main-1
track that govern movement east off those tracking into the Park Street
control point. The visible portion of main 2 is already part of the
control point. The visible sections of the maybe-main-1 and forwarding
yard ladder are NOT part of an interlocking.

So, Mr. Burnett, your understanding is not so far off from reality.
Only certains tracks in the photo are technically part of an
interlocking.

My confusion is the polar opposite of Mr Burnett's. How can you have
dispatcher controlled power switches outside the interlocking (control
point)?  It seems counterintuitive to me, but they exist in Roanoke,
Bluefield, and Williamson at least, and probably elsewhere. I presume
there are timetable instructions governing movement through them, and
those instructions probably require permission from the yardmaster to
foul the switches. I guess it's just cheaper (and less complex) than
having a seperate signal for every yard track.


Joe Shaw
Christiansburg, VA
http://www.krunk.org/
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