Can anyone help explain what this signal protects ?

[John Webb]

You could abolish it, but then the platform starting signals would act as section signals - meaning less flexibility and some expensive design work and changes to the interlocking for a very small cost saving!

To amplify a bit, if the platform starting signals were to become 'section signals', each lever would need to be fitted with an electric lock so it couldn't be cleared until 'Line Clear' was given by Deganwy on the block instrument. Any move into even the three sidings close to the platforms would need permission from Deganwy as 'shunting forward into next section'.
Retaining signal LO9 as the single 'Section Signal' keeps life simple, has no capital expenditure associated with its retention, and no increased costs associated with maintaining several electric locks rather than one.

 

[edwin_m]

As I hinted above, signal L9 gives the flexibility to get a departing train out of the way of an arriving one even if the section to Deganwy is still occupied. It would also allow a train to shunt in and out of the sidings, although I'm not sure if those sidings are still there! As mentioned, modifying siganlling is very expensive and redundant facilities tend to be left in place until the whole area is re-signaled. I've no idea if there are any plans to re-signal at Llandudno.

 

[K.o.R]

I found this article to be of interest and it has pictures of black and white posted distant signals

http://www.lmssociety.org.uk/monologues/M09.pdf

The recommendation was for the Executive Committee to approve expenditure of £16,332 to carry out the necessary work spreading the cost over a three-year period with the following lines to be dealt with during 1929

I don't think you could buy a single signal for that nowadays

 

[Belperpete]

To amplify a bit, if the platform starting signals were to become 'section signals', each lever would need to be fitted with an electric lock so it couldn't be cleared until 'Line Clear' was given by Deganwy on the block instrument. Any move into even the three sidings close to the platforms would need permission from Deganwy as 'shunting forward into next section'.
Retaining signal LO9 as the single 'Section Signal' keeps life simple, has no capital expenditure associated with its retention, and no increased costs associated with maintaining several electric locks rather than one.

It also means that the pointwork is not in the block section, which makes things easier during failures.

 

[Joseph_Locke]

I don't think you could buy the design for a single signal for that nowadays

Fixed