Signal Indication into Branches Governed by TT/TO and MBS Rules...?

[NW Mailing List]

Does anyone know of a situation where the N&W used a Position Light Signal to govern movements entering unsignaled territory operated by Time Table + Train Orders under Manual Block Rules?  (The key here is that the track being entered had to be governed by Manual Block rules.)

Surely there must have been branches on the Pocahontas Division where a "dark territory" branch, operated under TT/TO + MBS Rules, left a main track at an interlocking, and this situation would have obtained. 

I would be curious to know what signal aspect was used on such a signal to indicate the condition of the Manual Block ahead. 

At least one other railroad which used Position Light Signals had a unique arrangement for this function. For "Clear Block" they used a regular "Clear" aspect in the top arm of the signal, over a "marker light" further down the signal mast. For "Permissive Block" they used a "backwards" Approach aspect in the top arm, over the same marker light further down the mast. The marker light was the tip-off that the signal was a Manual Block signal. `This may be a clue as to how the N&W handled the situation, although there were no such aspects in the N&W Rule Books. 

Isn't it a shame we do not have a set of Standard Plans for the N&W Signal Department (... if, indeed, such a document ever existed) ? 

-- abram burnett 

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