colin1501 wrote:Following from Steve's point, and slightly off topic location wise, the semaphore down starter at Billingshurst was replaced by a 3-aspect c/l in the 1970s, while the advanced starter remained a semaphore. The starter cleared to yellow when pulled off, and to green when the advanced starter was pulled off. However, it sometimes flickered from green back to yellow then green again, and I assumed from this that the feed to the yellow and green aspects was via the arm repeater on the advanced starter, the flicker occurring as the arm bounced before settling. Sound likely?
Colin
... very, Colin; in fact almost certainly I'd say.
And although not much related to the OP, this must surely still be relevant to the thread's title.
To elaborate on this sort of arrangement, until resignalling around 1973, the ECML's London area included New Southgate ("NS") and Cemetery (C) boxes.
NS's Down Fast Second Home
(think 'Starter' on other railways: And about 235 yards from Box, at the departure end of that station platform
) was a '4-aspect' 'searchlight' colour-light
(standard 3-aspect plus additional top lens, yellow or unlit), reading towards the mechanical semaphore Starter
('Advanced Starter': 1,066 yards from Box), and with its double yellow provided to act as C's Outer Distant.
The semaphore Starter had C's mechanical semaphore Inner Distant below it.
If C was switched out or had cleared his signals before NS, then if, after clearing the Second Home 'Off' to one yellow, NS pulled the mechanical Starter vigorously, clearing both semaphore arms at the same time, it caused them
(remembering the 1,066 yard-long wire run to the stop arm) to rapidly move above, through, below, and back into, the range of degrees detected as properly 'OFF', but also the actions of the usual elements of the mechanical slotting meant that the two arms did not do this in synchronisation.
So, as the aspects of the colour-light Second Home were controlled by the arm position contact boxes of both semaphore arms, the result was briefly a rapidly changing veritable light show at the end of the platform, as the signal flashed through YY, R, G, R, Y, YY etc.,
(sometimes managing to do the cycle around 1 1/2 - 2 times) until the arms settled at 'Off' and the colour-light became steady green.