I am a little fuzzy on exactly where a dwarf signal should be located. I know they are in yards but are they also used anywhere else? I was told some times before a regular signal but that doesn't seem to make any sense. Would they be used for example in an engine serving facility?
Thanks
they are used primarily in terminal areas and to control movement out of sidings etc. they would not be used where a train approaching at high speed would need to know the signal indication while still some distance from it.
look at the arrangement of the throat of a major passenger terminal for a good example of their usage.
their physical size permits their placement between tracks where there would be no room for a high signal or need for a signal bridge.
they are, in most instances, interlocked to the switch or plant they govern and are controlled from a remote location such as a tower or by the dispatcher.
i personally have never seen one used in an engine terminal or on yard track for that matter exept where the lead joins the main line. but, then again, i haven't seen everything.
grizlump
Dwarf signals (or any other block signals) are rarely used in yards. Only major yards might have signals on their departure leads or other lead. They would not normally be used in an engine terminal.
Most dwarf signals are used to control movement out of sidings or industrial leads/trains onto the main track or controlled siding, or on main tracks where there is constrained vertical clearance. They are also used in terminal areas where signal masts would be impractical. Dwarf signals can only dispaly a few indications so they have limited use.
Dave H. Painted side goes up. My website : wnbranch.com
There are dwarf signals where the Port Road (NS along the Susquehanna below Harrisburg) joins the North East Corridor at Perryville, Maryland. They control the access from the Wye onto the NEC main.
Lee
Route of the Alpha Jets www.wmrywesternlines.net
I've seen dwarf signals in use on mainlines where traffic normally moves in one direction on each track.
In Pennsylvania between Altoona and Cresson, the outside mains were signaled for one direction (right-hand running) with dwarf signals for trains moving against the normal flow of traffic. The middle main is signalled in both directions.
On the former B&O in Fostoria, the B&O's route used to be signaled for right-hand running with dwarf signals at interlockings for anything moving against the normal flow of traffic.
Basically, from everything I've read on railroad signals, dwarf signals are used in slow-speed locations. In the examples listed above, the trains going against the movement of traffic would be running at slow speed and not normal speed.
Kevin
http://chatanuga.org/RailPage.html
http://chatanuga.org/WLMR.html
"Dwarf signals...are used extensively in interlocking plants where speeds are slow. The aspect of a dwarf signal is equivalent to that of the bottom head of a three-head interlocking signal. Dwarf signals protect minor track entrances to interlocking plants, serve as starting signals in large passenger terminals, or guide movements at junctions in heavy traffic areas, especially where slow speeds are required."
- "How To Operate Your Model Railroad" by Bruce Chubb, page 109
He also notes they could be used to signal trains temporarily going the wrong-way on a track, like a train going south on the northbound track of a double track mainline for example.
On the CSX around Atlanta, the rule of thumb for dwarf signals seems to be protecting a non-signalled track entering an interlocking (control point), such as a controlled siding, industrial spur, house track, etc. Regarding the PA comment above- On the former PRR coming out of Conway yard through Rochester, PA, there are still four tracks signalled for right hand running. The two westbound tracks have a cantilever signal bridge while the two eastbound tracks have dwarf signals. Jamie
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