Mike Hodgson wrote:Obviously not applicable to a tunnel mouth banner, but where banner signals are of the doubled sided type, it would be both both quadrants at the same time, which version you see depending on which side of the post you are.
Bob Davies wrote:Like scarpa, I do not think there is any such thing as a double-sided electro-mechanical banner so speculating on how it might work is at best academic. If someone can show me such an animal, I should be fascinated and then is the time to discuss its operation.
RichardH wrote:Double sided banners were mentioned in the thread below, although unfortunately my pictures of the one formerly at Lingfield are no longer available on this site. Basically it was a single small banner arm in a case glazed front and rear as it was mid-way along a platform. It was illuminated by bulbs in the top of the case and showed UQ on the approach side.
John Hinson wrote:Whichever way they indicate is pretty academic as long as it is 45 degrees and it becomes even less significant if they are repeating colour-light signals.
davidwoodcock wrote:Not quite academic, John. The Southern, at least, sometimes used Sykes banners as tunnel distants (either end of Penge Tunnel being an example but there were others) and it was obviously very desirable that their movement should mimic that of the semaphore starters mounted above them (even though I have been surprised to come across SR examples where working UQ and LQ arms were mounted on the same signalling structure).
John Hinson wrote:I don't see why it is desirable at all. I doubt many drivers give (or gave) the slightest thought to what we choose to call "upper" or "lower" quadrant when all they are looking for is a black bar which is either horizontal or inclined at 45 degrees.
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