Hey, grab those sirens and the subway hum, then do a quick pitch‑shift down on the siren so it sounds like a low‑end boom. Layer that with a tight four‑beat loop made from the train’s click‑clack, but slice it into 16‑step stutter and time‑stretch it so each hit syncs with a kick you drop in. Throw a side‑chain compressor on the whole mix so the kick keeps the groove pumping. Add a little reverse reverb to the edges of the train clatter for that airy rush, and then sprinkle some high‑frequency synth stab from a nearby traffic light. Keep the tempo around 120‑130 BPM, and when the crowd starts moving, let the siren line grow louder—just enough to feel like the city’s pulse. That should turn the sidewalk into a moving dance floor. Good luck!