Cab Signals Come to Boston's North Side

Well the mystery is over, it appears that at least some of the North Side MBTA lines (former Boston and Main) are not only getting the ACSES PTC system, but also the Rule 562 cab signaling arrangement that also comes with it.  Moreover it is triggering the replacement of searchlight signals that were considered safe only a year ago like those that used to be at WINCHESTER interlocking on the New Hampshire Route Main Line.  

At this point the cab signals are in service between some point north of North Station (likely SOMMERVILLE interlocking) and WINCHESTER interlocking in Winchester, MA.  While the MBTA has actually fitted some of its searchlights with 562 'C' boards, the ones in Winchester got the LED tri-light treatment. While this line segment had been recently re-signaled, the section between WINCHESTER and the Anderson Regional Transportation Center featured at least two locations with bi-directional, twin head searchlight masts that would display the rare Double Green Clear signal aspect. 

 The spread of Rule 562 across the MTBA North Side could mean the extinction of this once popular signal aspect.  The good news is that the joint Guilford freight trackage should preserve some populations of wayside intermediate signals and the MBTA has shown a willingness to preserve some legacy searchlights.  Fingers crossed.  I will hopefully be able to get up to the Boston area in the March 2021 time frame to document whatever remains.