What is a dwarf signal? Whenever I see a picture that mentions one, it looks like a meerkat standing in tall grass. Wouldn’t you want the signals to be up about eye level to the engineer?
Here are two typical examples of dwarf signals.
Dwarfs are commonly used in station approaches, in part for clarity in respect to which signal governs which track. A signal bridge spanning 10 tracks and holding ten signals could be confusing. In other areas, they serve as a signal for trains operating against the normal flow.
At any rate, they are always low-speed signals.
we have one lowly dwarf left. It is always red. However when there is going to be an inbound on that track - it winks at me. [:I]
Dwarf signals usually protect the entrance to yards, interlockers and controlled sidings, such as station approaches, passing sidings or industrial sidings.
Note the top signal in Jim’s photo is displaying a lunar on top…this would tell the crew the switch is lined for the siding, and to proceed at restricted speed…
The top signal shown is a B&O CPL dwarf. The top white light is refered to as the pilot light and is in fact a white light, not Lunar. Lunar aspects are displayed on the signal face itself when appropriate for the operation. The B&O CPL system used Pilot lights above and below the signal face to qualify the indications displayed on the signal face itself. The absence of a pilot light also conveyed a specific signal indication. The indication displayed on the pictured signal is ‘Approach’ - Approach the next signal prepared to stop and is the same indication that would be displayed on a ‘High’ signal for the same track conditions.
I have a question about Pennsy dwarf signals. I’ve seen some that have the vertical edge on the right and some that have them on the left. Is there any reason for each or were they just installed with whatever was on hand?
Kevin
OK that makes sense-sort of like the arrow on the back of a parking meter, that says: “this meter/this space”. Why are they “dwarf”? It seems like in a northern climate, the snow on the side of the tracks could sometimes be as tall as the dwarf signal.
Look at it this way–you’ve got a track (or a direction on a track) where trains can move at no higher than slow (in eastern parlance) or restricted (in anybody’s parlance) speed. Why waste a tall pole with three heads when you can convey the equivalent aspect–same indication–with something close to the ground that shouldn’t be able to be missed (snow notwithstanding–signals were kept visible by the same folks who swept the switches)? Eliminating confusion, as Paul mentions, is also part of the story.
Having said that, I’m not sure what the story is on that B&O dwarf CPL. It is conveying an Approach aspect, as stated. Without the “pilot” light on top, it would be a “Slow Approach”, which I would think would be the most one could get at any spot in which a dwarf signal would be deployed. Any comments from a B&O person?
I suspect that dwarf signals are becoming less common. Low-speed routes just don’t seem to be being built any more. If a stretch of double track is converted to CTC, all tracks at a given point are considered to be equals, and would rate a high signal–usually indicating a “Diverging” or “Medium” aspect instead of “Slow” or “Restricting”.
Also remember that until 1985, the FRA required signals to be to the right or directly above the track governed. Most places there isn’t room for a full height signal mast.
While many dwarf signals are only capable of displaying slow or medium speed, the B&O CPLs can show the entire range of signal indications from Clear to Stop. Note, that, as BalACD said, the B&O CPLs use pilot lights above and below the main light cluster, where other road used a second or third signal head.
As for snow, it’s not as much of a problem as you’d think. First off, the signal maintainers can shovel the signals out. Second, the heat generated by the lamps is often enough to melt the nearby snow.
Nick
Thanks for the explanations guys. It’s obvious, that my area doesn’t have enough lines and traffic to warrant fringe benefits like dwarf signals.[;)]
Those are B&O Dwarfs. Probably.
Dwarfs is not a “Lessor” signal. They present information that is just as vital as the “Big signals”
This particular CPL is interesting because Lunar Blue is availible at the 4o clock and 10o Clock position
…Need to find Dan Harmon’s doctored photo and drop that rascal in here (from when Mooks first asked about dwarf signals)[:D]
…The concern of snow obliterating the dwarf signal as one of the above posters noted would be a {first}, thought of mine too…It certainly happens in Winters I’ve seen {in the east, many times}, that could bury that short stature signal quickly.
Perhaps the saving grace would be the heat the lights inside would melt an opening {in time}, to allow it to be visible…But why did they take the chance of them being buried, at least for part of the time…??
Even the built in small snow plow {on engines}, could cover it right after some track worker had shoveled it clear…
Jim’s bottom photo is of a former PRR dwarf signal. Used to be that all of those lights would be white, but I guess the stop indication was changed to one red light instead of two horizontal white ones.
Can’t explain the question about why some of these would be oriented one way and some the other–unless there were two sides to some of them.
I’ll ask on the PRR forum I belong to and report back. Good question.
I think in the Bruce Chubb book, in the section on prototype signalling he says a dwarf signal would be the equivalent of the lowest head in a three-headed signal.
This is the response from an ex PRR employee who is now the President of the PRRT&HS.
Typically the dwarf signal was located on the engineman’s side of the
track at interlocking limits to control trains moving against the
current of traffic. In multiple track territory it’s quite possible to
see them on what appears to be either side of the track but they are not
both controlling movements on the same track.
No. No. No.
Pennsy dwarf or pot signals can only display slow speed. However, both B&O CPL, and Reading/NYC style Color Light pot signals can display aspects authorizing maximum track speed. Check the NORAC book…green over green on a pot is Clear.
This signal is on Main track, and is capable of displaying Clear (two greens with a pilot). Not shown is another pot governing the track on the right, also capable of displaying Clear.
Nick
I wasn’t referring to their importance, only to their height.[;)]