...looks to me like standard knob and tube wiring, a venerable and now much-maligned way of doing things that conserved wire and did a good job of dissipating heat. The 'knobs' in this instance are two-conductor ceramic insulators rather than the more common single conductor knob.

It's hard to be certain how the luminaire is tied-in, but I'm betting that the thick spot near the round box is a soldered splice, carefully wrapped with rubberized tape where the insulation had been removed to make the join.

@Vintagetvs: clutches maybe? ["I can't seem to figure out how that one pulley in the center appears to be rotating but nothing else is?"]

In case of fire, fill bucket with 1 gallon of water, throw on flames, repeat as necessary.

[Those fire buckets were generally filled with sand. - Dave]

The "main" line shaft is segmented, you can see two control arms (hanging down at about a 60deg angel) they're connected to a "throw out bearing" (note the Y connection at the bearings) these control arms engage/disengage the large driven pulley's. from the "live" main line shaft.

I recall that it took a special eye/touch to "throw" the control arms at the right time or else you got quite a kick off the control arm.

A great picture of old industry!

P.S. they don't make em like they used to!

Exposed, rigid conductors, with movable clamps to pick the power off for each lamp. There really is very little that's truly new, eh?

You used to see a lot of it in Germany, often with the conductors at odd angles, but that's all low voltage. From the bulbs and the other fittings, I'd say this is "house current."

the three guys nearest in the camera are able to carry on working whilst everybody else is intent on staring at the photographer.

I can't seem to figure out how that one pulley in the center appears to be rotating but nothing else is?

Wonder where the main power source is, off to the left out of view perhaps?