Yesterday I visited Osterley and Boston Manor stations, hoping to see and photograph the distinctive light towers during twilight, this being a time when the light is clearly visible but there is also still sufficient daylight to see areas away from artificial illumination.
At Osterley the lights worked, but were dim. Somewhat like a lamp with a 10 watt light bulb rather than a 150 watt light bulb. Nevertheless, my visit was successful. The best view came from the other side of the footbridge over the tracks just beyond the station - the chain link mesh fence was useful in acting as a tripod.
By way of contrast, my visit to Boston Manor was unsuccessful, as the light was not illuminated. The only saving grace was that I saw the Asset Inspection Train languishing in the depot.
I remember there were access issues getting to the areas behind the roundels at Redbridge. This meant re-lamping was no longer possible.
Health & Safety considerations ruling out the use of traditional long ladders.
maybe a bank of LED's at the bottom of the tower shaft facing upwards would work? I am thinking of ceiling panel lights designed for offices, etc. It does not need to be brilliantly bright - just enough to be seen against the darkness of the air around the tower.
A lighting solution I am seeing more of is lamps at a high (but easily serviceable height) and mirrors on a (high) ceiling reflecting the light back down. Seems to work well, perhaps a similar solution could be employed in this case?