Yellow plastic tags on signals

'These signals have been fitted with LEDs'?

Asset Identification?

They are tags from the civil engineers; I've seen them but can't remember what they say.

Labelling things as 'safe' is fairly silly when you think about it. A tested for electrical safety sticker doesn't make an appliance safe. A green tick on a ladder doesn't prove it's not deteriorated (or been damaged) since the last inspection. I'm sure most signal technicians would realise when a ladders not safe to use, but it can't be proven without a training course, so a little yellow tag becomes neccessary.
That said the way things seem to be going, the ladders will be removed and it will be a week long possession to set up a full scaffold providing a fully Accessible* access and work platform, have it checked and double checked and...

I often use ladders (and 'alternative' - less appropriate) access equipment in my job. I have seen talk of outlawing the use of ladders, and relying more on access towers and powered lifts etc. It would mean great expense in equipment and training costs (and as I work mainly on a freelance basis, it might be down to me to pay for my own training), and it would take longer to get to the various positions one needs to go. Yes you can fall off a ladder easier than from an aerial work platform, but i don't think it's ever going to be reasonably practical to never use them.

* MIP / VIP / HIP / MHU ... compliant

Possibly not as early as the '30s - the LER box is most likely a 'pool' repair.

The conversions to colour light signalling at the west end of the District territory were:

Acton/Hounslow West July '32/'33
South Harrow Sept '49
East of Acton - west of Turnham Green Oct '51
T. Green - West Ken March '52
West Ken - E Ct. Oct '52
Ealing Bdwy Nov. '52
ECt East - Cromwell Rd Dec. '52
ECt West - Putney May '53
Ealing Cmn - Hanger Lane Nov. '53

With the conversions to programme machine working Turnham Green (Sept '63) and Hammersmith (Dec. '63) saw a lot of signals relettered, partially to do with the provision of 'X' signals but also to do with the change to same number ^A, ^B, ^C signal heads. No signals were moved or taken out of commission. Conversely, the conversion at Acton and Ealing Common (July '65) saw a lot of signals altered principally moving them eastwards on both lines; I guess any of those moved would have their ladder examined; the same is true of the Earls Court area (conversion in May '67) saw a fair bit of stageworks prior to the swap. Ealing Broadway and Hanger Lane record no movements of signals for the automation in May '74.

It is worth remembering that signal ladders (even for colour lights) are made of of pretty long-lasting stuff, more often than they are made out of wrought iron. Wearing another hat, I've been up a couple of signal ladders that date from pre-Grouping days.

;D ;D Yeah, I was being an S&T technician, rather than a TT person!

This strikes me as storing up a problem for the future - ladder is tagged as being safe, before the scheduled re-inspection date someone needs to replace the bulb. They check the tag, which tells them it's safe, so they climb the ladder. Unfortunately between being tagged and the technician climbing it, it has become unsafe such that the technician falls off and is injured. Technician sues Metronet/LU/TfL/whoever and (very likely) wins.
If the technician is unlucky and falls onto a juice rail, it is not unlikely the HSE will prosecute under the Electricity At Work Act/HASAW, etc Act.

As a result of this, all people climbing ladders must verify the safety of a ladder before using it - which they would have done before - except they now must fill out a form to say they've done it, leading to it taking more time to fill it in, and by the people who have to process the form. Additionally, every single penny spent on the yellow tagging programme has been wasted.
Quite likely also that HSE now insist that electricity must be turned off, verified off (and recorded several times by several people that it has been so verified) before the ladder can be approached = more, time, money, effort and destruction.

That's fairly standard in avoiding red and green clothing of whatever type.