Yeah, reminiscent of scenes from old movies, you'd have to keep crooks talking long enough to manually trace engaged selectors through the exchange. If a crook hung up before a trace was completed one mightn't have the full number but only half of it, this at least could place cops in the right ballpark/area.

If you're a crook another great advantage of step-by-step Strowger exchanges is that the only indication that a call has been made from one's telephone is a single incremental relay-type counter on one's telephone line for the purpose of charging the customer—one click on the counter one call. Unless someone is standing by the counter in the exchange when a call is made then the time of the call and the number phoned would never be recorded.

Given privacy violations and such shenanigans these days it seems to me one doesn't have to be a crook to benefit from ancient Stronger switch exchanges.

Shame they've all now bitten the dust just when we need them.