electric cabinet

[NW Mailing List]

This is the block occupancy indicator that was at the Catawba branch switch (as the story goes). It was given to me by my father who had acquired it from Section Forman Hamlin of Salem.  





Chuck Akers
Roanoke, VA
540-815-1275

> On Dec 19, 2020, at 8:47 AM, NW Mailing List <nw-mailing-list at nwhs.org> wrote:
> 
> 
> My guess, FWIW, is that the little device is being used as a **Motor Car Indicator.**
>  
> Many railroads used Motor Car Indicators.  They told a motor car operator whether a train was in the block, or not.  When you think about that, you realize that it is not very useful information.  Suppose a train were in the second block away, and rapidly approaching?  Railroad had explicit instructions about what the motor car operator muse see on the indicator, before he was allowed to place his car on the tracks. Of course, there were also other safeguards in place, which generally was the Line-Up System, which were kinda-sorta neither safe nor guards.
>  
> Many railroads, at the time they installed automatic block signals, went for one mile long signal blocks (i.e. spacing for the automatics.)  This was done due to heavy volume and high speeds.  Over the years (and into the 1980s,) railroads were lengthening their signal blocks to two miles, both to eliminate redundant equipment and to accommodate the braking profiles of longer and much heavier trains.  It would be interesting to examine N&W track charts from the 1920s, 1930s, 1940s, and calculate the average length of signal blocks.
>  
> Many railroad did not have AC power available along their main tracks, but did have plenty of low voltage DC made by primary battery cells (Zinc + Copper + acid,) made up in glass jars.   For those railroads, the signal supply companies made electro-magnetic devices operated by DC current and NOT equipped with an electric lamp. (Reason:  Lamp filaments are current hogs, but electro-magnetic relays can be made to operate on as little as 0.020 amps (twenty one thousandths of an amp.)  These devices were worked by an electro-magnet relay, driven by a secondary battery circuit and operated over a contact in the track relay.  The armature of the device drove a linkage which rotated, by one-half turn, a disc behind a glass window.  One half of the disc was painted red, the other half white.  When no train was approaching, the white half of the disc shown behind the glass window;  when a train was in the block, the red half shown behind the glass. 
>  
> Interestingly, the rotating disc type indicators were also used in N&W stations and telegraph offices to indicate the approach of trains.  Salem Passenger Station had two of them in the agent's office, one for the eastbound main track, and one for the westbound.  Bassett station also had two of them, one to indicate northward approach on the single main track, the other to indicate southward approach.   The N&W obviously used them in other locations as well.  Unfortunately, I was never able to find one of those.
>  
> Why would the man in a depot need to know when a train was closely approaching?  Because he needed to get the Train Orders and Clearance Card wrapped up and in the string, for delivery.  Because he was selling tickets and hustling baggage and express, and needed to know when the passenger train was about to arrive at the platform.  And cetera.
>  
> The N&W also used incandescent lamps housed in small sheet steel housings for indicating the approach of trains.  The attached photograph shows two of them.  The black one is from the Park Street Switchtender's Box at Roanoke, and the green one is from Q Telegraph Office at Payne, on the Roanoke & Southern.  Lamp lit = no train approaching;  lamp extinguished = train in block.
>  
> BTW, I should mention that the little indicator in the photo at Bedford is NOT a Position Light lamp housing.  Its rear door access betrays it as an incandescent lamp housing made for use behind the roundels of a semaphore signal.  Railroads were masters of the fine art of repurpose-scrounging...
>  
> -- abram burnett,
> plausibly deniable turnips
>   
> <N&W_Block Indicators_2016_01_21_#020.jpg>
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