In Worcester, Massachusetts, is a junction where four directions of traffic meet and interchange: CSX’s Boston Line and the Providence and Worcester Railroad. The two lines are briefly tangent to each other and do not cross; the only interaction between them is what is essentially a universal crossover.
The P&W is unsignaled at this location, but the crossovers onto CSX track are directly within CP44, a signaled interlocking in CTC territory. CSX has signals at all of its entrances to the interlocking…but the entrances from the P&W have no signals whatsoever. These two crossovers are unsignaled entrances into a signaled interlocking.
For those who’d like technical details on the CSX signal installation, this is NORAC Rule 261 territory (movement on signal indication, in any direction) and Rule 562 is also in effect (cab signals with wayside signals at interlockings only – no wayside automatic block signals).
Is this type of interlocking agreement common? How is authority granted for trains to enter the interlocking and signaled territory?
You say there is not P&W signals…what are you going by? A main line like the CSX’s here, would usually be protected by signals at all four corners and all tracks intersecting. I suspect the P&W’s signals are dwarf or low signals or are further back from the crossing itself to stop trains where they do not foul other tracks, sidings, platforms, sight distances, road or other crossings, and whatever I didn’t mention here. Not having a book of rules and timetable for either road it is difficult to actually determine. But the interlocking should be protected by signals on both roads.
Just looking a the Google Map view - I would suspect the Normal position for the switch on the P&W is lined for the P&W. There appears to be a ‘post’ just to the East of the P&W switch, which I suspect may be a Statuatory Stop post for P&W trains. Up near the clearance point of the line to CSX - there appears to be a Dwarf Signal on the South Side of the P&W connecting track. I would suspect that the switch on the P&W to the connecting track is Electric Locked and can only be used with the permission of the CSX Train Dispatcher - the Dispatcher may even have direct control of the Electric Lock and must initiate a action on the CADS system for the lock to be ‘unlockable’ after the crew is given verbal permission to operate and unlock the switch. After using the switch the crew must report clear of the switch and return it to the P&W routing and Dispatcher would activate the lock again. Movements totally on the P&W would operate in accordance with P&W rules.
Disclaimer - I have no first hand knowledge of this location.
It turns out I was looking in the wrong place. I stopped by today and found dwarf signals right at the clearance point of the eastern switch - not at all where I was expecting them. I couldn’t see the other entrance but I would imagine there’s another dwarf signal there.