Sorry, this is a quick verification thread to avoid posting non-existen problems in Technical Reports. I was running behind another train on the Bakerloo Line (Southbound - towards Elephant&Castle) and in the section between Charing Cross and Embankment there is a small ~440 yards section with only 2 signals, A361 at the exit of Charing Cross and then X355 about 90 yd down the line. ->|Char.X|--|A361| --90yds--|X355|-->to Embnkmt. Now the problem is that while X355 was showing a full red aspect, A361 was showing a green aspect without any amber/yellow signal in between. I'm sorry for the bad quality but this post is just to double check, if someone that knows the LU signaling can tell me it's true to real life to have a green followed by a red without any yellow signal in between.
Turns out a bit of googling would have answered my question: A signs can only display red or green, same for X signs if used like A signs (like in this case) the only signals that can display a yellow aspect are repeatears (which are identified as Rxxx), but are used only where needed, which is clearly not this case. Sorry for wasting your time and creating a pointless topic.