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| Unusual Signals 13/10/2014 at 11:52 #65026 | |
Gwasanaethau
509 posts |
Hi all, Here’s another question about strange signals in London. This time it’s about a signal I saw at City Thameslink. It was situated roughly half-way along the northbound platform. Unfortunately, when I saw it a couple of months ago, I was in a rush and didn’t have time to photograph it. I have since come across an identical one (see attachment) part-way down Platform B at St. Pancras. There were a couple more at St. Pancras’s Thameslink platforms pointing in various directions on both lines; and, it seems, yet more in and around Smithfield Sidings. Anybody know what they are? They seem to show normal 4-aspect signals – could they be miniature repeaters of some sort? Thanks again! Mark (Gwasanaethau) EDIT: forgot to say: I apologise for the photo quality – it was taken with my phone. Post has attachments. Log in to view them. Last edited: 13/10/2014 at 11:53 by Gwasanaethau Reason: Additional Info on Photo Quality Log in to reply |
| Unusual Signals 13/10/2014 at 12:15 #65028 | |
mfcooper
707 posts |
It is a mid-platform signal that is a combined 4-aspect signal and a Proceed On Sight Authority (POSA) signal. The top right LED can display Green or Yellow, the bottom right LED can display Red or Yellow, giving a 4-aspect signalling sequence. The top left and middle right LEDs display the flashing diagonal white lights that represent a proceed POSA aspect. Log in to reply The following user said thank you: Gwasanaethau |
| Unusual Signals 13/10/2014 at 15:49 #65034 | |
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GW43125
495 posts 
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" said:It is a mid-platform signal that is a combined 4-aspect signal and a Proceed On Sight Authority (POSA) signal.I didn't realize it had a PoSA! I thought it was just a call-on! You learn something new every day, as they say! Log in to reply |
| Unusual Signals 13/10/2014 at 19:11 #65041 | |
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mfcooper
707 posts |
" said:...could they be miniature repeaters of some sort?No repeating here. It is a stop signal. It just reduces the headway for the next train arriving into the platform. Log in to reply The following user said thank you: Gwasanaethau |