Very grateful that we no longer have all those wires and battery boxes for light bricks.

How technology has changed.

Times sure have changed. The amount of battery power required for a couple of lights then is pretty much just within a single self-contained brick now.

This is honestly a really cool set. Does it stretch the definition of a set, maybe. Is it something great? Yes! I really wish they still sold supplementary sets nowadays, and this is no exception. I really wish Lego had more lighting parts, and it’s a shame they did it in the 60s, but not now. Also, this is another (sort of) train related set, so I’ll say it for all of us, BRING BACK TRAIN.

Well, it’s definitely showcasing that there are lights involved. Models, not so much. And at 4.5v back in those days, I suspect the intensity is wildly exaggerated.

I had this when it was first released. Very sophisticated with its coloured signs and filters, compared with what I had a couple of years earlier (445-2)!

You know, I think that's 122 in the middle upper picture. Two VSotWs in a row!

I can't imagine these are LEDs, so the power requirements and heat output must be no joke.

Most people don't realize this set brought us the first colored transparent bricks (Tr. Yellow, Tr. Green and Tr. Red).

The printed transparent signs were nice too. The pre 1980s electric system maybe not so much.

EDIT:
Since all the talk about LEDs - those (and the 9V system lamps till the late 90s) were indeed your classic (tungsten wire) light bulbs.
Power efficiency might be really bad, but I never noticed any heat enough to be critical for the surrounding plastic. After all you don't want these to be on for hours (they'll likely break by that type of usage anyways).