I'm installing dwarf signals to indicate turnout setting, using green
for normal and yellow for diverging. Usually normal is straight and
diverging is the curved or angle leg of the turnout. I just reached a
place where straight takes the train into the yard and curved
continues on the main line. Would the prototype signal the straight
as diverging (yellow) and the curved as normal (green)?
It depends. If you are using "route signaling" (where the interlocking
signals tell the engineer what route he is lined up to take), then having
the main line curved route show green and the route into the yard show
yellow could be appropriate. In the US after about 1900, particularly on
the big eastern roads (PRR, NYC, B&O, etc.), "speed signaling" became
popular (where the signals tell the engineer how fast he can go, but not
necessarily which route he is taking). In this case, you might want the
route into the yard to show "slow clear" which is often green on a dwarf,
and the main line route to show "limited clear" (often flashing green on a
dwarf) or "medium clear" (sometimes green over flashing red on a dwarf)
depending on how sharp the turnout is (limited speed is often 45 mph, medium
30, and slow 15). Geezer
TMTC currently uses this style of signalling throughout it's entire
system. PNWR *might* be doing the same between Wilsonville, OR and
Beaverton, OR since PNWR's passenger operations are in conjunction
with TMTC; it wouldn't entirely surprise me if TMTC engineers end up
taking the controls on PNWR's trackage once their joint passenger
The "problem" there is the use of the term "straight".
Different railways used different terms, such as "main" and
"diverging"or secondary". Using those terms the curve becomes "main" and
the straight becomes "diverging".
PS Ignore the ensuing posts from Ray, Steve, etc which will point out
that I'm anti-american, racist, stupid, syphilus laden, Bin Laden, ...
On 11 Mar 2008 20:16:41 GMT, firstname.lastname@example.org (Calvin
As a rule the "normal" route would be for a main track (which could be
a main line track, a yard lead, branch line main track, etc...), and
the "reverse" route would be an auxillary route such as a yard track,
an industry track, etc. In most places the rules say switches must be
left in the "normal" position when you are done using them, except
under certain circumstances. This way future trains arriving would
not have a switch against them on a main route. In yards, often
certain switches are designated to be left in a certain position but
most switches in most yards are not designated, because there is not
"normal" route. Most railroads require trains to move at restricted
speed looking out for improperly lined switches in yards, so in most
areas of the year there is no necessity for such rules regarding
normal and reverse routes, unless it is specified in timetable
instructions for whatever reason.
A common example would be generally they want switches to be left
lined AWAY from engine terminals, repair tracks, and so forth unless
you are in the process of entering or leaving those facilities..
On Fri, 7 Mar 2008 12:30:44 -0800 (PST), "Old.Professor"
Whatever route the main track takes would be considered the normal
route. whether some type of dwarf signal is used, or a simple metal
target on the switch, you would show the "clear" route for the main
route and "diverging" for the auxillary tracks.
Just as an example, the Freight Lead at Inman Yard in Atlanta GA takes
a sharp turn to the right at the #3 switch on the south end, if you
continued straight you'd go down Forwarding Yard Three, but the right
turn continues on down the freight lead. The target on the #3 switch
is white for the freight lead and red for Forwarding Yard #3 (and so
are the rest of the targets down that ladder.
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