Mickey wrote: ↑Wed Jul 21, 2021 6:19 am
Slotted signals...
Interesting in what you said maybe a year ago regarding the Up slow and Up slow to Up fast line semaphore stop signals carried on a bracket post to the left of the Up slow line just off the Up slow line platform at New Barnet station because I didn't realize that signal was a 'slotted' signal and worked by both New Barnet North and New Barnet South boxes?. I always thought something was funny about that signal because New Barnet South box would be obviously 'switched out' (all the South box signals would be pulled off on all running lines) and then you would roll into the Up slow line platform on a Cravens unit sitting behind the drivers compartment and watching the road ahead and you would see that signal being pulled off to clear?. The distant signal beneath the slotted stop signal was obviously Oakleigh Park's Up slow line outer distant signal.
I've gone back four years in this thread but can't find a post of mine referring to those signals being slotted Mickey.
In fact
(apart from the usual slotting for distants under stop signals), there were originally no signals slotted by both of the latter South and North boxes of our days at New Barnet.
But there were originally four signals south of the station (2 distants, 2 stop signals), control of which was transferrable between the boxes, and interlocked by being released by an Annetts Key which had to be in the box needing to work them.
The four signals
** had been what were normally South's Down Fast and Slow Distants, and his Up Fast & Slow Homes. But control of the four was transferred from the South to the North by conveyance of the Key
(which was only released by the levers of South's six other signals needing to be left 'Off' being Reverse), by the South signalman to North when South switched out, with the reverse of the process being necessary when South was to Switch In. Therefore while the Key was on the way between boxes, the 'transferrable' signals could not be worked at all, so South switching in and out not only needed the usual Regulations' requirements of the status of all the Block Sections, but a margin of up to about ten minutes between all Up trains if delay was to be avoided.
** - By the late 1960s the 'transfer' arrangement had become applied to only three of the original four signals
(South's Down Fast Distant had been made motor-worked, and so was 'electrically slotted' thus no longer needing South control of it to be transferrable), and also one of the three that still had to be 'transferred' (South's Up Fast Home) had been changed from a mechanical to an electrical arrangement when it became a colour-light.
