[ThJ]

I think all those trains, cars, carriages and people would’ve made a lot more noise than the audio mix suggests. The trains and cars especially should be drowning out everything else as they pass near the camera. This sounds more like the audio track of a feature film than anything captured with a microphone in the field.

[Piskvorrr]

Of course it wasn't captured, it's a modern audio track applied to a colorized+upscaled, originally silent film.

Silent films (which meant that literally no audio track was recorded) did depend on the cinema creating one, either through people literally banging on cans, through an orchestra, to an outright Rube Goldberg contraption: https://psmag.com/environment/sound-effects-in-the-silent-mo...

[lakkal]

At 00:05 there's a credit for 'Ambience sound by guy jones', so I think as someone else said, the sound was added later.