Shenandoah Division Cab Signals -- Unresolved Questions

[NW Mailing List]

ABE 

 

   Here’s what little I know N&W cab signals never had color roundels . Indication was aluminated  letters H-high speed S medium speed and L low speed  see attach from US&S pic from a pallet, and they were  latter changed to PL indications per N&W drawing  (I got but can’t find at the moment )  Like the one in my collection attach pic ,  Also wiring diagram operation drawing   C-32367

 

Larry Evans

 

      

 

From: NW-Mailing-List [mailto:nw-mailing-list-bounces at nwhs.org] On Behalf Of NW Mailing List
Sent: Tuesday, May 02, 2023 10:38 AM
To: N&W Mailing List <nw-mailing-list at nwhs.org>
Subject: Shenandoah Division Cab Signals -- Unresolved Questions

 

We all kick ourselves for the questions we never asked while there was still living memory to provide an answer.  And this one is no different. 

 

The N&W's Shenandoah Division was equipped with cab signaling, but the north and south ends of the Division were equipped with different types of equipment. 

 

The north end had the early Loop-and-Track technology, which depended upon steady-energy AC currents being in-phase or out of phase. 

 

The south end of the Division used the much more modern Coded Track principle of the 1930s, whereby an AC current was pulsed into the rails at different pulse rates, and those pulses were picked up by the engine's detector bar, amplified and decoded to give an in-the-cab indication of the condition of the next signal block ahead. 

 

The use of different technologies (and thus different equipment) on the north and south ends leads to some interesting QUESTIONS : 

 

1.  Were engines assigned to the Shenandoah Division equipped with BOTH cab signal technologies, so they could be used on either district of the Division ?   

 

2.  If so, did a passenger engine on a Hagerstown-Roanoke run have to cut one one technology at Shenandoah, and cut in the other technology? 

 

3.  If so, where were the cut out controlls located, and was the change-over performed by the Egineman or a round house electrician ? 

 

The attached photos show a Union Switch & Signal cab signal display box of the same type used on the Shenandoah Division (top row, left end.)  Lamps behind the roundels were probably 32 volt lamps, as that was standard voltage on steam engines and early D-thingies as well. 

 

When I worked on the Shenandoah Division in the 1960s, I asked some of the old Hog Heads for details about how the cab signals functioned, and their answers were conflicting and obviously confused.  Several of them could not even remember the colors of the glass roundels !  So the matter of a good description of the equipment and its operation still seems to be an open issue, at least for me.  Obviously there were written instructions covering all these matters.  Have they been found? 

 

-- abram burnett, 

Industrial Strength Liquid Turnips - 200 Proof 

 

  

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