Dwarf Signal Lights.

Discussion in 'Model Rail Operations' started by tetters, Feb 25, 2008.

  1. kutler

    kutler Member

    Really, Ever heard of the Nickel spur?

    Signaled yard tracks are quite common.

    While the vast Majority of the Nickel spur is other than main track a small portion where this track gains entry to the Cartier Sub is signaled through a cross-over track.

    IIRC the best indication for a westbound move to the Cartier Sub would be a Slow Clear indication, which means proceed through the turnout at slow (15 MPH) speed after which time you may proceed at track speed as the block is clear. For movements to continue on the Nickel spur the indication would be a restricting signal. (max 15)

    In general pot signals usually convey slower indications such as Medium and Slow speeds through cross overs or turnouts.

    Pot signals often called dwarf signals are often employed as economy or where it's desired to avoid confusion for main track movements. I.E. Some railroads signal the ends of siding tracks with Pot signals.

    A good book to read is called "Railroad Operation and Railway Signaling" by Phillips. It was originally published in 1941, reprinted and reasonable to obtain, the information still applies to modern railway signaling principals.

  2. acsoosub

    acsoosub Member

    That's really not the same thing as signalled yard tracks. The branchline has that short piece which is CTC controlled along with the adjoining crossovers on the mainlines. On either side it's all uncontrolled, and as per the original discussion in this there are no switches at all in the yards to indicate the directions of switches in the yard. Yard crews throw their own switches within the yard and have to be able to tell which direction they're thrown themselves, by looking at the switch stand targets or points. (This is why speed limits in yards are always restricted speed - have to be able to stop in half your line of vision or short of switches and obstructions.) Tracks joining the mainline or other signalled tracks will have signals controlling the junction, but that's usually pretty much it.
  3. kutler

    kutler Member

    I take it were not on the same page here. The subject of this thread is dwarf signals. What's relevant to the topic then is the track which is CTC controlled(signaled) and not the unsignaled spur (not branch) beyond. Incidentally the Nickel Spur is named the Sudbury yard lead immediately east of the CTC control location.

    In railway rules tracks have to be designated for the purpose of issuing authorities like TOPs and slow orders. CROR rule 51 specifies the naming of main tracks. Likewise other than main tracks have to be designated using such names like running track, running lead, long lead, or other terms to describe a signaled yard track where such authorities are issued.

    In your earlier posts you made two other remarkable comments suggesting that there are not hand thrown switches on signaled main tracks, and Tracks joining the mainline or other signaled tracks will have signals controlling the junction, both false.

    If you had meant to say yard ladder tracks or yard classification tracks are not usually constructed as signaled yard trackage, it would be more factual.

    Yard tracks that are commonly signaled are hump leads, arrival/departure group tracks, shop leads, spur and junction connections such as our example above. These are prime locations for dwarf signal placement.

  4. acsoosub

    acsoosub Member


    OK, I think we weren't really talking about the same thing there. The original discussion in this thread talked of using dwarf signals to display the direction of switches in the yard proper which certainly wouldn't be done in prototype practice.

    I guess I was far too broad in my other statement, and in doing so made it inaccurate. Tracks joining other signalled tracks would be pretty much the only place to find dwarf signals; but you wouldn't find them on every track entering a signalled mainline, which looking back at what I wrote previously is what my statement implies. That's definately inaccurate and I misspoke there. Dwarf signals would mostly be at dispatcher controlled switches (or tower or otherwise centrally controlled), and certainly not at any hand-thrown spurs etc.

    An example; at Guelph Junction, where the CPR's Hamilton subdivision meets the Galt, the switch for the east leg of the wye is controlled by the dispatcher and is protected by a dwarf signal on the connecting track. The west leg only handles a few trains and is not protected. You can often hear on the scanner trains getting a rule 568 permission to enter the main track at that mileage.

    I don't believe I ever suggested there are never hand-thrown switches on the mainline, just that switches in the yard itself would pretty much all be hand-thrown. (Except obviously at a hump for example).
  5. kutler

    kutler Member

    I don't understand what you mean by this statement then.

  6. kutler

    kutler Member

    In some larger yards there are route indicator signals, while looking similar to dwarfs, are often controlled by someone, but don't usually convey authority to use track. CN Symington has extensive route indicated switches. I believe that colours used are green and yellow to indicate route. Not likely used in this application is Red, which under most circumstances means stop.

    CP Calgary yard has a interlocked dwarf signal within the yard. This signal has been violated numerous times by crews who assume it's just another indicator light.

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